Effect of heptachlor on certain aspects of carbohydrate metabolism in Swiss albino mice.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
M R Rao
Publications and source records attributed to M R Rao.
Identification and sequence characterization of a 1.3 Kb EcoRI repeat fragment that harbors a DNA repair site of rat pachytene spermatocytes.
Introduction of well-programmed nicks and gaps and the associated DNA repair activity in the genome at the pachytene interval is a characteristic feature of the meiotic prophase in organisms as varied as lilium and mouse. In the present study we have shown that the DNA synthetic activity in rat pachytene spermatocytes is insensitive to aphidicolin, a specific inhibitor of DNA polymerase alpha, delta and epsilon, suggesting DNA beta-polymerase-mediated repair synthesis in these cells. We have developed a novel approach for the isolation of the DNA repair sites by combining two independent techniques. Following incorporation of BrdUrd into pachytene spermatocytes in the presence of aphidicolin, the repair sites were released as ssDNA fragments by treatment of nuclei with 30 mM NaOH. Subsequently, the BrdUrd containing ssDNA fragments were specifically isolated using polyclonal anti-BrdUrd antibodies. The DNA fragments released were of two size classes, namely 4-7S (major) and 9-12S (minor) and constituted approximately 1.75% of the pachytene genomic DNA. These DNA repair fragments were distinct from Okazaki fragments and other replicative intermediates isolated from rat bone marrow cells as evidenced by (a) their different size distribution and (b) little cross-hybridization. Southern hybridization of restriction enzyme digests of rat genomic DNA with probes made against BrdUrd-ssDNA fragments revealed that although the repair sites were distributed throughout the genome, strong hybridization signals were observed in EcoRI. (1.3 kb and 2.4 kb), BamH1 (9 kb) and HindIII (5 kb) repetetive DNA fragments. The EcoRI 1.3 kb family were cloned into M13 mp19, and a repair positive (1.3 A) and a repair negative (1.3 B) were identified and sequenced. The repair positive clone contained (a) (CA)22 repeat, (b) a (CAGA)6 repeat and (c) 4 sequences sharing high homology with various hypervariable minisatellite (HVMS) sequences. One of the HVMS sequence contained a GGCAGG motif known to be responsible for germline instability. The repair negative clone had (a) (CA)6 repeat and (b) a HVMS like sequence without GGCAGG. The significance of these motifs and their relevance to the events of DNA metabolism at pachytene interval have been discussed.
Animals↗
Family latrines and paediatric shigellosis in rural Bangladesh: benefit or risk?
BACKGROUND: The potential benefits of installing excreta disposal facilities on the burden of paediatric diarrhoea in less-developed settings remain controversial. We conducted a longitudinal study to evaluate whether family latrines are associated with interruption of the transmission of shigellosis to younger children in rural Bangladesh. METHODS: We prospectively studied 1529 children under 5 years of age exposed to index cases of Shigella dysentery. In all 219 children with culture-proven shigellosis detected during 1 month of follow-up were compared with 1310 control children who did not develop shigellosis or Shigella-negative dysentery. RESULTS: Overall, the presence of a family latrine appeared to be associated with a higher, not a lower, risk of paediatric shigellosis (adjusted odds ratio (ORa) = 1.37, 95% confidence interval (CI): 0.99-1.89). While use of a pit or sanitary latrine revealed no evidence of a protective association (ORa = 0.96, 95% CI: 0.43-2.15), use of a hanging latrine in which faeces were discharged directly onto the ground or into a body of water was associated with a notable increase of risk (ORa = 1.42, 95% CI: 1.02-1.98, P < 0.05). CONCLUSIONS: While cautioning that installation of sanitary latrines may not be sufficient to reduce the burden of paediatric shigellosis in less-developed settings, these data suggest that eliminating unsanitary latrines constitutes a potentially important intervention in its own right in these settings.
Age Factors↗
Comparison of heated water-filled mattress and space-heated room with infant incubator in providing warmth to low birthweight newborns.
BACKGROUND: Prevention of excessive heat loss is fundamental to survival of low birthweight (LBW) newborns. The use of infant incubators (INC) is beyond the resources of developing countries, and the space-heated room (SHR) has been the only feasible means of providing thermal protection to LBW newborns. Recently a thermostatically controlled, heated, water-filled mattress (HWM) has been developed as a potentially simpler and affordable alternative. METHODS: In a neonatal care ward of a referral hospital in Addis Ababa, 62 < 1 week old newborns, weighing 1000-1999 g, who were well enough to breathe comfortably in room air and tolerate oral feeds, were randomly allocated to INC, HWM or SHR and followed for 3 weeks. The level of cold stress as assessed by core-to-skin temperature gradient and the rate of weight gain were the main outcome measures. RESULTS: The level of cold stress was lowest in the INC, intermediate in the HWM and highest in the SHR. Relative to the INC group, the HWM group exhibited a modest increase in the occurrence of clinically important hyperthermic or hypothermic deviations in core temperature (rate ratio (RR) = 2.3; 95% CI: 0.9, 5.6), and the SHR displayed a definite increase (RR = 4.0; 95% CI: 1.7, 9.3). During the first week, the rate of weight gain was highest in the INC group (3.6 g/kg/day), lowest in the SHR group (-2.3 g/kg/day, P < 0.05 versus INC) and intermediate in the HWM group (1.6 g/kg/day, P > 0.1 versus INC). CONCLUSION: Care in the SHR produced clinically significant thermal stresses and was associated with deficient early neonatal growth, but the use of HWM may constitute a feasible and clinically acceptable alternative in providing warmth to LBW newborns during the neonatal period.
Beds↗
Human mismatch repair genes and their association with hereditary non-polyposis colon cancer.
Explore the source record for details and available documents.
Biological Evolution↗
Behaviour of the germ cell specific lamin through mammalian spermatogenesis as probed with monoclonal antibodies.
We had earlier identified a 60 kDa nuclear lamin protein (lamin(g)) unique to the germ cells of rat testis which was subsequently shown to be antigenically conserved in germ cells of grasshopper, rooster, frog and plants. We have now obtained eight monoclonal antibodies in mouse against this lamin(g) antigen. While all the eight Mabs reacted with lamin(g) antigen in an immunoblot analysis, only three Mabs (A11C7, A11D4, C1F7) showed strong reactivity in the immunofluorescence analysis of the germ cells. The Mabs A11C7 and A11D4 showed a slight cross-reactivity with rat liver lamin B. Indirect immunofluorescence analysis of pre-meiotic, meiotic and post-meiotic germ cells with Mabs have shown that while the lamin(g) is localized in the lamina structures of spermatogonia and round spermatids, it is localized to the phase dense regions of pachytene spermatocytes which is in conformity with our previous observations using rabbit polyclonal antibodies. The localization of the antigen in the germ cells was also confirmed by immunohistochemical staining of the thin sections of seminiferous tubules. By immunostaining the surface spread pachytene spermatocytes, the antigen was further localized to the telomeric ends of the paired homologous chromosomes. Using anti-somatic lamin B antibodies, we have also demonstrated the absence of somatic lamins in meiotic and post-meiotic germ cells. The lamina structure of pre-meiotic spermatogonial nucleus contains both somatic lamin B and lamin(g) as evidenced by immunofluorescence studies with two differently fluorochrome labelled anti-lamin B and anti-lamin(g) antibodies. The selective retention of lamin(g) in the pachytene spermatocytes is probably essential for anchoring the telomeric ends of the paired chromosomes to the inner nuclear membrane.
Animals↗
[Effects of m-nifedipine on activities of Na+,K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase in myocardium and brain of elderly renovascular hypertensive rats].
Clipping the left renal artery induced marked hypertension and hypertrophy of the left ventricle in elderly (24-month-old) rats. m-Nifedipine (m-Nif, ig 20 mg.kg-1, qd x 9 wk) significantly decreased the systolic blood pressure and the weight of the left ventricle in the renovascular hypertensive rats (RVHR). In RVHR, the activities of Na+, K(+)-ATPase and Ca(2+)-ATPase in microsomes of the myocardium and brain were reduced significantly compared with those in sham-operated rats. m-Nif was found to increase the activities of these enzymes of the myocardium and brain in elderly RVHR (P > 0.01). m-Nif 10-1000 mumol.L-1 in vitro elevated the activities of Na+, K(+)-ATPase and Ca(2+)-ATPase in the myocardium and brain of RHVR. On the contrary, the myocardial and cerebral Mg(2+)-ATPase activities were higher in RVHR than in sham-operated rats. m-Nif was shown to depress markedly this enzyme both in vivo and in vitro. These results indicate that m-Nif can improve the activities on Na+, K(+)-ATPase and Ca(2+)-ATPase in the myocardium and brain in elderly RVHR.
Animals↗
[Effects of m-nifedipine and nifedipine on hemodynamics in renovascular hypertensive rats].
In the renovascular hypertensive myocardial hypertrophic rats of prevention and regressive groups, the blood pressure was lowered by m-nifedipine (m-Nif) or nifedipine (Nif) of 20 mg.kg-1.d-1, i.g., for 9 wk vs control (LVH) group (P < 0.01). From the isolated working hearts of prevention and regressive groups, it was found that AP, LVSP, +dp/dtmax, -dp/dtmax, CF, and CI values of m-Nif and Nif groups increased higher than that of LVH group, but LVEDP and T was lower in m-Nif and Nif groups. It was concluded that m-Nif exhibits the similar effects like Nif in prevention and reversion of renovascular hypertensive LVH and improvement of hemodynamics.
Animals↗
Testis-specific histone (H1t) is not phosphorylated and has a weak interaction with chromatin.
Soluble chromatin was prepared from rat testes after a brief micrococcal nuclease digestion. After adsorption onto hydroxylapatite at low ionic strength, the histone H1 subtypes were eluted with a shallow salt gradient of 0.3 M NaCl to 0.7 M NaCl. Histone H1t was eluted at 0.4 M NaCl, while histones H1a and H1c were eluted at 0.43 M NaCl and 0.45 M respectively. The extreme divergence of the amino acid sequence of the C-terminal half of histone H1t, the major DNA binding domain of histone H1, from that of the somatic consensus sequence may contribute to the weaker interaction of histone H1t with the rat testis chromatin. Further, histone H1t was not phosphorylated in vivo in contrast to histone H1a and H1c, as is evident from the observation that histone H1t lacks the SPKK motif recognized by the CDC-2kinase or the RR/KXS motif recognized by protein kinase A.
Amino Acid Sequence↗
The human mutator gene homolog MSH2 and its association with hereditary nonpolyposis colon cancer.
We have identified a human homolog of the bacterial MutS and S. cerevisiae MSH proteins, called hMSH2. Expression of hMSH2 in E. coli causes a dominant mutator phenotype, suggesting that hMSH2, like other divergent MutS homologs, interferes with the normal bacterial mismatch repair pathway. hMSH2 maps to human chromosome 2p22-21 near a locus implicated in hereditary nonpolyposis colon cancer (HNPCC). A T to C transition mutation has been detected in the -6 position of a splice acceptor site in sporadic colon tumors and in affected individuals of two small HNPCC kindreds. These data and reports indicating that S. cerevisiae msh2 mutations cause an instability of dinucleotide repeats like those associated with HNPCC suggest that hMSH2 is the HNPCC gene.
Amino Acid Sequence↗
Safety and immunogenicity of the oral, whole cell/recombinant B subunit cholera vaccine in North American volunteers.
A newly formulated, oral, inactivated whole cell plus recombinant B subunit (WC/rBS) cholera vaccine was evaluated in US military personnel. In the first study, 74 subjects were given two doses 14 days apart. In the second study, 186 subjects were randomized into four groups; two groups received vaccine with either full (4 g) or half (2 g) strength bicarbonate buffer, and two groups received either full or half strength buffer without vaccine. Mild gastrointestinal symptoms were associated with full buffer (P = .02) but not with the vaccine. In the first study, 36% of all subjects and 55% with low prevaccination titers (< 1:40) had a > or = 2-fold rise in vibriocidal antibody level; > 80% of subjects developed a 4-fold rise in anti-cholera toxin (CT) titers. Post-vaccination IgA and IgG anti-CT titers were approximately 1.5-fold higher among persons receiving full strength buffer (P = .05). The WC/rBS vaccine is safe and immunogenic in North Americans, although some mild gastrointestinal symptoms occur with the high concentration of buffer necessary to protect the B subunit from gastric acid denaturation. Prior immunity to cholera conferred by parenteral vaccine decreased vibriocidal antibody response.
Administration, Oral↗
The epidemiology of antibody to hepatitis C in Egypt.
Explore the source record for details and available documents.
Adolescent↗
Risk factors associated with a high seroprevalence of hepatitis C virus infection in Egyptian blood donors.
We performed serologic tests for hepatitis C virus (HCV) infection on sera obtained from 163 volunteer blood donors seen at one Cairo hospital. We found HCV infection in 36 donors (22%) measured by a second generation enzyme immunoassay. Thirty-five of these 36 positive sera were tested with a second generation recombinant immunoblot assay (RIBA-2); 22 (63%) were reactive and another 12 (34%) showed an indeterminate reaction. Overall, 13.6% (95% confidence interval [CI] = 8.3-18.9%) of these Egyptian blood donors were serologically confirmed to be infected with HCV. Of several demographic variables and medical risk factors examined, the serologically confirmed (RIBA-2 reactive) donors were significantly older than nonreactive donors, and the age-adjusted risk of being HCV-positive was significantly greater in individuals residing outside Cairo. A knowledge of having received injections, of having a history of schistosomiasis, or of having concomitant hepatitis B surface antigen or antibody were significantly associated with an increased risk of HCV-seropositivity; however, after adjusting for confounding demographic factors, only schistosomiasis (odds ratio = 8.9, 95% CI = 2.35-33.52) was significantly associated with HCV infection. The HCV seropositive rate of 13.6% among Egyptians is 5-35-fold higher than that reported from volunteer blood donors in other countries. Screening for HCV should be instituted in Egyptian blood banks. Blood banks that do not test for HCV should include a history of schistosomiasis in their exclusion criteria used for routine screening of blood donors.
Adolescent↗
Effects of m-nifedipine on dihydropyridine binding sites in cardiac and cerebral cortex cell membranes from left ventricular hypertrophied rats.
m-Nifedipine (m-Nif 20 mg.kg-1.d-1 ig for 9 wk) decreased left ventricular weight in the renovascular hypertensive rats (P < 0.01). Though not significantly affecting the density of dihydropyridines (DHP) receptor (Bmax), m-Nif administered whether for prevention (6 wk postclipping) or for regression (9 wk postclipping), markedly decreased the total number of DHP binding sites in hypertrophied left ventricle (LV). m-Nif also reduced the dissociation constant (Kd) of DHP binding sites in the membranes of LV and cerebral cortex from cardiac hypertrophied rats (P < 0.01). These effects of m-Nif were similar to those of nifedipine (Nif) in the same dosage. The results suggest that m-Nif can prevent and regress the LV hypertrophy resulted from renovascular hypertension and reduce the total number of DHP binding sites in the membranes of LV from cardiac hypertrophied rats.
Animals↗
[Effects of m-nifedipine and nifedipine given intraduodenally on coronary flow, myocardial oxygen, and carbon dioxide metabolism in dogs].
In anesthetized dogs intraduodenal administration of m-nifedipine (m-Nif) 0.4 mg.kg-1, coronary flow increased from 708 +/- 72 to 880 +/- 150 ml.min-1.kg-1 (+24%) at 5 min, to 1976 +/- 350 ml.min-1.kg-1 (+179%) at 30 min, and to 998 +/- 250 ml.min-1.kg-1 (+41%) at 4 h. At the dose of nifedipine (Nif), coronary flow increased from 778 +/- 91 to 1080 +/- 90 ml.min-1.kg-1 (+39%) at 3 min and to 1836 +/- 280 ml.min-1.kg-1 (+136%) at 90 min. m-Nif was more 43% potent than Nif and the duration of action of m-Nif was longer. m-Nif reduced heart rate by -39%, while Nif reduced only -11%. m-Nif increased coronary sinus O2 content and reduced MVO2, and no difference was seen between these 2 drugs. However, the rate of CO2 production with m-Nif was reduced to a greater degree than that of Nif. The results indicated that m-Nif was more beneficial in alleviating myocardial ischemia than that of Nif.
Animals↗
Initiation of food supplements and stopping of breast-feeding as determinants of weanling shigellosis.
The association between the period elapsed since weaning and the risk of shigellosis was assessed between 1 November 1987 and 30 November 1989 for a cohort of 1085 Bangladeshi children aged < 3 years. The children were followed for 1 month after exposure to Shigella spp. in their residential neighbourhoods, and the 268 who developed microbiologically confirmed (n = 118) or clinically presumptive (n = 150) shigellosis were compared with the 817 control children who did not develop either syndrome. No increase in risk was noted among breast-fed infants who received food supplements within the previous 3 months compared with those who had received supplements for longer (adjusted odds ratio (OR) = 1.2; 95% confidence interval (CI) = 0.4-3.0). However, compared with breast-fed children, non-breast-fed children had an increased risk (adjusted OR = 2.0; 95% CI = 1.3-2.9; P < 0.001), which was largely attributable to a substantially increased risk in the 3 months after stopping breast-feeding (adjusted OR = 6.6; 95% CI = 2.9-14.6; P < 0.001). The early post-cessation risk was equivalent for confirmed and presumptive shigellosis, but was particularly pronounced among the severely malnourished (adjusted OR = 10.2; 95% CI = 3.1-33.3; P < 0.001). This complex temporal pattern of risk highlights the need for precise definitions of weaning to facilitate identification of children at high risk for invasive diarrhoeal syndromes.
Bangladesh↗
[Protective effects of m-nifedipine and nifedipine in isolated ischemic-reperfused rat hearts].
The protective effects of m-nifedipine (m-Nif) and nifedipine (Nif) were studied in isolated rat hearts subjected global ischemia and reperfusion. After global ischemia for 30 min followed by reperfusion for 10 min, left ventricular (LV) compliance and developed pressure (DP) were severely declined, LV stiffness constant was significantly increased (P < 0.01). Previous treatment with m-Nif or Nif prevented changes of LV compliance, stiffness constant and DP caused by ischemia and reperfusion. No marked difference in potency between m-Nif and Nif was observed.
Animals↗
Impact of Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine on responses to concurrently administered diphtheria-tetanus-pertussis vaccine.
OBJECTIVE: To assess whether serum antibody responses to diphtheria-tetanus-pertussis (DTP) vaccine were affected by coadministration of Haemophilus influenzae type b capsular polyribosylribitol phosphate polysaccharide-tetanus protein (PRP-T) conjugate vaccine when given to patients at 2, 4, and 6 months of age. DESIGN: Randomized, double-blind clinical trial. SETTING: Urban Santiago, Chile. PATIENTS: Healthy infants assembled from health centers. Two hundred seventy-eight (74%) of 375 eligible infants participated; 222, who complied with the complete protocol, constituted the primary group under analysis. INTERVENTIONS: One of three vaccine regimens was given to study participants at 2, 4, and 6 months of age, either DTP mixed in the same syringe as PRP-T (group 1); DTP and PRP-T given at separate injection sites (group 2); or DTP without PRP-T (group 3). PRIMARY OUTCOME MEASURES: Titers of serum antidiphtheria toxoid, antitetanus toxoid, and pertussis agglutinin antibodies were measured in blood samples taken from patients 2 months after each dose. RESULTS: Serum antidiphtheria toxoid and antitetanus toxoid responses showed no important depressions in the patients receiving PRP-T. In contrast, geometric mean titers (GMTs) of pertussis agglutinins, expressed as reciprocal serum dilutions, after both the second and third doses (GMT2, GMT3) were lowest in group 1 (GMT2 = 89; GMT3 = 1230), intermediate in group 2 (GMT2 = 123; GMT3 = 1995), and highest in group 3 (GMT2 = 210; GMT3 = 3090; P less than .05 for trend group 1 less than group 2 less than group 3 after each dose). Antipertussis toxin and antipertussis filamentous hemagglutinin antibody titers also were depressed in patients who received PRP-T. Follow-up of a subset at 18 months revealed an expected decline of pertussis agglutinin titers to near baseline levels in each group. CONCLUSIONS: Concurrent administration of PRP-T vaccine with DTP vaccine, either in the same syringe or at different sites, interfered with antipertussis responses to a primary series of immunizations. Although the clinical significance of this antagonism is uncertain, these data underscore the caution required in decisions to add new vaccines to existing immunization regimens.
Antibodies, Bacterial↗