Microplate nitrate reductase assay versus Alamar Blue assay for MIC determination of Mycobacterium tuberculosis

A rapid colorimetric, microplate based nitrate reductase assay (NRA) method for minimum inhibitory concentration (MIC) determination of clinical isolates of Mycobacterium tuberculosis was compared with the microplate Alamar Blue assay (MABA), presently in vogue. Reproducible results were obtained in 7 days by NRA. The NRA method was found to be inexpensive, suitable for MIC determination against M. tuberculosis and can be suggested as an ideal substitute to MABA.

Cloning, sequencing and partial characterisation of sorbitol transporter (srlT) gene encoding phosphotransferase system, glucitol/sorbitol-specific IIBC components of Erwinia herbicola ATCC 21998

A DNA fragment of approximately 1500 bp, harbouring the sorbitol transport gene (srlT), was amplified from the chromosomal DNA of Erwinia herbicola ATCC 21998 by PCR and cloned in Escherichia coli JM109. Degenerate oligonucleotide primers used were designed based on the conserved regions in the gene sequences within the gut operon of E. coli (Gene Bank accession no. J02708) and the srl operon of Erwinia amylovora (Gene Bank accession no. Y14603). The cloned DNA fragment was sequenced and found to contain an open reading frame of 1473 nucleotides coding for a protein of 491 amino acids, corresponding to a mass of 52410 Da. The nucleotide sequence of this ORF was highly homologous to that of the gutA gene of Escherichia coli gut operon, the srlE gene of Shigella flexrni and the sorbitol transporter gene sequence of Escherichia coli K12 (Gene Bank accession nos. J02708, AE016987 and D90892 respectively). The protein sequence showed significant homology to that of the phosphotransferase system i.e. the glucitol/sorbitol-specific IIBC components of Escherichia coli and Erwinia amylovora (P56580, O32522). The cloned DNA fragment was introduced into a pRA90 vector and the recombinant was used for developing srlT mutants of Erwinia herbicola, by homologous recombination. Mutants obtained were unable to grow on minimal medium with sorbitol. The insertion of the pRA90 vector inside the srlT gene sequence of the mutants was confirmed by DNA-DNA hybridisation.

Anti-HCV seropositivity among multiple transfused patients with beta thalassaemia

Hepatitis C virus is considered to be the main aetiological agent responsible for the occurrence of post-transfusion hepatitis. Patients with thalassaemia acquire hepatitis most often from viruses contracted through blood transfusions. The present study was undertaken to evaluate the prevalence of hepatitis C virus (HCV) in thalassaemic patients with multiple blood transfusions. The association of HCV seropositivity with number of blood transfusions and liver enzyme profile was also analysed. The study group consisted of fifty patients (40 males and 10 females) attending the thalassaemic unit of Lok Nayak Hospital, a tertiary care hospital at Delhi, within the age group of 1-25 years. Thirty patients (60%) were found to be seropositive for HCV antibodies while one patient (2%) was co-infected with HCV antibodies and hepatitis B surface antigen. Study of liver enzyme profile showed aspartate aminotransferase levels to be significantly higher, although the level of serum alanine aminotransferase, alkaline phosphatase, total protein, bilirubin and albumin were not significantly altered in these patients. It is inferred from this study that 60% of the thalassaemics were infected with HCV and this was directly related to the number of blood transfusions received by them. The regularised national blood policy followed by blood banks for providing safe blood along with better screening method of donated blood in blood banks would bring down the incidence of hepatitis C in such high risk group.

Primary small bowel tumors: a radiologic-pathologic correlation

BACKGROUND

Primary small bowel tumors are rare and their preoperative diagnosis is unsatisfactory. The cornerstone of diagnosis remains contrast radiography. The present study was done to evaluate the radiologic findings of primary small bowel tumors as shown on enteroclysis and to correlate these observations with surgical and histopathologic findings.

METHODS

Seventy two patients with primary small bowel tumors identified by enteroclysis were evaluated. All the patients were subjected to jejunal biopsy or surgery. The diagnosis was established by histopathologic examination in all cases.

RESULTS

Radiologic findings were suggestive of benign tumors in 19 patients and malignant tumors in 31 patients. Nonspecific findings in the form of diffuse involvement of the small bowel were noted in 22 patients. There was 100% radiologic-surgical correlation. Leiomyomas and lymphomas were the most common benign and malignant tumors, respectively. Tumor specificities were 89.5% for benign tumors and 41.5% for malignant tumors.

CONCLUSION

Distinctive morphologic patterns as shown on enteroclysis are highly suggestive of specific tumor types in the majority of cases.

Incidence of anaerobes in throat infections and their sensitivity pattern in Ludhiana

Of 175 throat swabs processed, anaerobes were isolated from 16 (9.14%) patients. Isolation of anaerobes from healthy controls was 2 out of 25 (8%). Peptostreptococci and Bacteroides species were the commonest isolates followed by Peptococci and Propioni-bacterium. All of these isolates were sensitive to Metronidazole. Clindamycin, Erythromycin and Tetracycline also showed good response.

Potentiation of analgesia and reversal of tolerance to morphine by calcium channel blockers

Effect of four calcium channel blockers (CCBs) belonging to different chemical classes, alone and in combination with morphine was investigated on two models of pain sensitivity, i.e. formalin and tail flick tests in mice. All the studied CCBs, i.e. diltiazem, flunarizine, nimodipine and verapamil inhibited formalin-induced pain responses; however, with verapamil, though there was a trend towards a reduction of paw-licking response to formalin, it was not found to be statistically significant. In contrast, none of the CCBs affected the tail flick latency at any of the doses studied. Morphine, a mu-receptor agonist exerted a significant analgesic effect in formalin as well in tail flick tests. Pretreatment with all CCBs significantly enhanced the analgesic effect of morphine in both tests of nociception. Further, concomitant administration of one of the CCBs, diltiazem with morphine prevented the development of tolerance to the latter. However, combination of diltiazem with morphine, like morphine alone was found to be ineffective in morphine tolerant animals. Results, thus, show that CCBs produced an analgesic effect of their own in formalin-induced tonic pain and potentiated the analgesic activity of morphine. They also modulated opioid-induced tolerance.

Purification and characterisation of an ester hydrolase from a strain of Arthrobacter species: its application in asymmetrisation of 2-benzyl-1,3-propanediol acylates

An ester hydrolase (ABL) has been isolated from a strain of Arthrobacter species (RRLJ-1/95) maintained in the culture collection of this laboratory. The purified enzyme has a specific activity of 1700 U/mg protein and is found to be composed of a single subunit (Mr 32,000), exhibiting both lipase and esterase activities shown by hydrolysis of triglycerides and p-nitrophenyl acetate respectively. Potential application of the enzyme concerns the asymmetrisation of prochiral 2-benzyl-1,3-propanediol esters besides enantioselective hydrolysis of alkyl esters of unsubstituted and substituted 1-phenyl ethanols.

Portal and mesenteric venous calcification in patients with advanced cirrhosis

OBJECTIVE

The incidence of calcification in the portal and mesenteric venous system was studied in patients with advanced cirrhosis undergoing evaluation for liver transplantation. The significance of portal and mesenteric calcification on liver transplantation was also investigated.

CONCLUSION

An 11% incidence of portal and mesenteric venous calcification was found in patients with cirrhosis, which was much higher than anticipated. Two (29%) of seven patients who had calcification present on CT and underwent liver transplantation died at surgery as a result of portal venous thrombosis. Thus, venous calcification seen on CT is a significant finding in patients undergoing liver transplantation.

The pyrroloquinoline quinone synthesis genes of Gluconobacter oxydans

A Tn5-induced glucose dehydrogenase (GDH) deficient mutant of Gluconobacter oxydans IFO 3293 was characterised. DNA sequencing showed that the insertion site occurred in an open reading frame with homology to the pqqE gene. It was shown that acid production could be restored by addition of the coenzyme pyrroloquinoline quinone (PQQ) to the medium. The pqq cluster of G. oxydans ATCC 9937 was cloned and sequenced. It has five genes pqqA-E. The cluster could complement the Tn5-induced mutation in IFO 3293. Pulsed-field gel electrophoresis suggested that the pqq genes are not closely linked to the ribF gene that produces the riboflavin cofactor for the gluconic acid dehydrogenase.

A review on recent development of common cold therapeutic agents

(1) The common cold is a frequently occurring illness caused by rhinoviruses. Inspite of its ubiquitous occurrence the disease has defied all efforts of finding a cure. The current approaches to the treatment of common cold can be divided into two important categories: the antiviral and antiinflammatory; both of these leave a lot to be desired. Most of the rhinovirus serotypes use a single cellular receptor, i.e. the intercellular Adhesion Molecule-1 (ICAM-1) for attachment to the cells. This has lead to the development of blockers of this receptor in an effort to find a cure for the common cold. (2) Recently tremacarmra, a synthetic ICAM-1 glycoprotein has been investigated in human volunteers as an antiadhesion molecule towards an approach to common cold therapy. Two dosage forms of the compound-phosphate buffered saline spray and carboxymethyl cellulose-mannitol powder spray were administered intra-nasally in two modes--pre-inoculation (7 h prior) and post-inoculation (24 h after) time periods of rhinovirus type 39 challenge to different groups of human volunteers. Both the treatment modes produced a significant decrease in the symptoms score of clinical illness and concentration of interleukin-8 in the nasal lavage. Saline spray was found to be devoid of any side effects, whereas powder spray produced some nasal irritation initially. The encouraging results of clinical trial with tremacamra show that a cure for common cold is not far off. However, it remains to be seen what would be the impact of such synthetic protein administration on the immune response of the body, should such compounds be used repeatedly. Further, since all colds are not due to rhinovirus it would be wise to restrict the use of tremacamra during autumn and spring when rhinoviruses are known to be the causative organisms of common cold.

IL-12 and IL-2 potentiate the in vitro tumor-specific activity of peripheral blood cells from cervical cancer patients

We have carried out a detailed analysis of the cellular immune functions of cervical cancer patients in comparison with healthy controls. It has been observed that the freshly isolated peripheral blood mononuclear cells (PBMC) exhibit natural cytotoxicity (NC) against a number of targets including tumor cells, mainly delivered by NK cells, which are non-adoptive and MHC unrestricted. Upon stimulation with cytokines like IL-2, IL-7, IL-12, IL-15 and interferons, PBMC acquire lymphokine activated killer (LAK) activity which enables them to lyse a wide range of targets including fresh tumor cells and virally infected cells. We compared the effect of IL-2 and IL-12 on enhancement of NC of PBMC from cervical cancer patients. IL-12 stimulated cultures (CD3+, CD56+) exhibited significant levels of tumoricidal activity. IL-2 stimulated lytic activity sustained even after 10 days while that of IL-12 stimulated cells declined after 6 days. Activation of PBMC was marked by increase in the expression of activation marker CD45RO and adhesion molecules LFA-1alpha, ICAM-1 and CD44. Addition of IL-12 to IL-2 stimulated cultures further enhanced the degree of lytic activity. Our data, thus, provide an evidence that PBMC from cervical cancer patients can be stimulated in response to cytokines and local or systemic treatment with low doses of cytokines may help to yield a better immune response against virus infected tumor cells in cervical cancer.

Interaction of pentazocine with calcium channel blocking drugs during chemical and thermal pain in mice

The present study was designed to investigate the antinociceptive interaction of a clinically used opioid, pentazocine which produces its analgesic effect mainly through kappa receptors, with some calcium channel blockers (CCBs, viz. Diltiazem, flunarizine, nimodipine and verapamil--each representing one chemical class) in formalin and tail flick tests in mice. All the CCBs, except verapamil, significantly inhibited the formalin-induced pain response in a dose-dependent manner. However, none of these drugs affected tail flick latency at any of the studied doses. Pentazocine showed a significant antinociceptive response in both pain models, although a high dose was required to increase the tail flick latency. Pretreatment with all CCBs, individually enhanced the analgesic effect of pentazocine in both formalin and tail flick tests. In the latter test of nociception, a per se ineffective dose of pentazocine, showed a significant analgesic response in presence of CCB dose which itself was not effective in the test. Chronic concomitant administration of diltiazem with pentazocine did not prevent the development of tolerance to the opioid compound. However, diltiazem when given in combination with pentazocine to pentazocine-tolerant animals, it effectively reversed the tolerance. Results of the study thus suggest that concomitant treatment with CCBs, irrespective of their chemical nature, not only potentiate the antinociceptive effect of pentazocine in opioid naive animals in both tonic and acute nociceptive tests but also reverse the pentazocine tolerance.

A mutant of gluconobacter oxydans deficient in gluconic acid dehydrogenase

Gluconobacter oxydans ATCC 9937 was subjected to transposon mutagenesis using Tn5. A non-pigmented mutant was shown to be defective in gluconic acid dehydrogenase and to produce gluconic acid from glucose, whereas the parent strain produced 2, 5-diketogluconic acid. Cloning and sequencing of the region containing the Tn5 insertion showed that the insertion point occurred in an open reading frame homologous (42% amino acid identity) to the ribF genes of Pseudomonas fluorescens and Escherichia coli. The resulting lack of a riboflavin cofactor would explain the loss of enzyme activity.

Enteroclysis-guided fine-needle aspiration cytology of focal small-bowel lesions

PURPOSE

To study the role of enteroclysis-guided percutaneous fine-needle aspiration cytology (FNAC) of focal small-bowel lesions.

MATERIAL AND METHODS

Twenty patients with non-palpable circumscribed small-bowel lesions found on enteroclysis underwent FNAC after confirmation of needle position under fluoroscopy.

RESULTS

Positive diagnosis was obtained in 18 (90%) of the patients. Thirteen patients with positive FNAC and one with inconclusive cytology underwent surgery. In all, the cytological diagnosis was confirmed by histopathology. No complications were seen.

CONCLUSION

Enteroclysis-guided FNAC of focal small-bowel lesions is a safe and accurate diagnostic method.

Comparative pharmacokinetics of amikacin following a single intramuscular or subcutaneous administration in goats (Capra hircus)

The pharmacokinetics of amikacin sulfate was investigated following a single intramuscular (i.m.) or subcutaneous (s.c.) administration (10 mg/kg). The plasma concentration versus time data were analysed using the biexponential equation for first-order absorption and elimination phases for both the i.m. and s.c. routes. The absorption half life values for the i.m. and s.c. routes were found to be 14.64 and 12.36 min, respectively. The biological half-life values of amikacin following i.m. and s.c. routes were found to be 84.46 and 93.96 min, respectively. The systemic availability of amikacin for both the i.m. (102.15 +/- 5.08%) and s.c. (106.82 +/- 12.95%) routes was found to be almost complete. Thus, based on the data of short absorption half life, almost complete systemic availability, slightly longer biological half life and ease of administration, we suggest that the s.c. route be preferred over the i.m. route for amikacin administration in goats. Amikacin at a dose level of 8 mg/kg body weight at 12 h intervals would result in a therapeutic peak plasma concentration (Cpmax) of 32.30 micrograms/mL, which is not expected to produce any oto- or nephropathic effects.

Teenage primigravidae: a comparative study

A review of history sheets of obstetric cases recorded in a district hospital in 1992 was done to compare the obstetric outcome in 200 teenage first pregnancies (Study group) with that in Control group i.e. 20 years to 29 years. It revealed that incidence of complications of pregnancy like anaemia, pregnancy induced hypertension (PIH) and preterm labour were significantly higher among teenage mothers. The normal mode of delivery was commoner in teenagers (82.5%) in comparison to control group (76.5%), probably because of higher number of low birth weight babies. The fetal outcome was significantly worse in teenage mothers with high incidence of perinatal mortality (8%) and low birth weight babies (35%). There was not a single newborn with birthweight above 3500 gms, in teenage group, whereas, control group had 5 babies (2.5%) in the category.

Transposon induced mutation in Gluconobacter oxydans with special reference to its direct-glucose oxidation metabolism

Transposons are important genetic tools for mutation studies and for location of genes in prokaryotes. However, very little published work is available on transposon mutagenesis in Gluconobacter oxydans. We report here Tn5-induced mutation in a keto acid-producing strain of G. oxydans ATCC 9937 with special reference to the direct-glucose oxidation pathway operative in this organism. In this study, a mutant deficient in glucose dehydrogenase (GDH) activity has been developed by Tn5 mutagenesis. The data of plasmid profiles in the wild-type and the GDH- mutant are indicative of transposition in the first instance on one of the three plasmids (pVJ1) harboured by the organism, resulting in rearrangement of the plasmid and finally stable transposition of Tn5 on the main genome. The final location of Tn5 on the genome has been established by DNA hybridisation studies.

Endoscopic stenting of minor papilla for symptomatic pancreas divisum

Pancreatitis is one of the presentations of pancreas divisum. Endoscopic treatment by dorsal pancreatic duct stenting relieves symptoms in a majority of patients. We report a patient with pancreas divisum and calcific chronic pancreatitis in whom successful drainage of the dorsal duct with a stent through the minor papilla relieved the pain.

An analysis of sampling errors for the Demographic Health Surveys

"Sampling errors and design effects from 48 nationally representative surveys conducted under the Demographic and Health Surveys Program for a large number of variables concerning fertility, family planning, fertility intentions, child health and mortality etc. are analysed for the total sample, and for urban-rural domains, sub-national regions and various demographic and socio-economic subclasses.... At the country level, overall design effect (the ratio of actual to simple random sampling standard error) averaged over all variables and countries is around 1.5. Variation among countries is high, but less so than among variables. Urban-rural and regional differentials in design effects are small, and can be attributed to the fact that similar sample designs and cluster sizes were used across those domains within each country. Design effects for estimates over other subclasses are smaller, and tend towards 1.0 for small subclasses and differences, apart from the effect of sample weights which tends to persist undiminished across variables and subclasses." (SUMMARY IN FRE)

Identification and function of type-2 and type-3 ryanodine receptors in gut epithelial cells

Reverse transcription-PCR (RT-PCR) techniques were used to identify the expression of ryanodine receptor (RyR) isoforms in gut epithelial cells. Restriction digest and sequence analysis of the PCR product showed the presence of RyR 2 and RyR 3. [3H]Ry binding studies on a microsome preparation, in a high-salt buffer, showed specific binding with an EC50 of 15 microM. In order to determine a potential functional role for these RyRs, we first characterized the response of the cells to acetylcholine. At all concentrations used acetylcholine induced sinusoidal cytosolic Ca2+ concentration ([Ca2+]i) oscillations. In response to 10(-4) M acetylcholine, levels of inositol 1,4,5-trisphosphate (InsP3) showed a peak of six times the basal level, at 30 s after stimulation. Application of caffeine alone failed to elicit a rise in cytosolic Ca2+. However, caffeine (5-50 mM) did rapidly and reversibly inhibit the acetylcholine-induced [Ca2+]i oscillations. The effects of Ry were more complex. Applied alone, Ry had no effect on the [Ca2+]i signal. When applied during agonist-evoked [Ca2+]i oscillations, Ry (10 microM) slowly blocked the response. In the continuous presence of Ry (10 microM) a short application of acetylcholine elicited a [Ca2+]i response that continued as oscillations even when the agonist was removed. The oscillations, in the presence of Ry (10 microM) but absence of agonist, were blocked either by removal of extracellular Ca2+ or by an application of a higher concentration of Ry (100 microM). These effects are consistent with the known use-dependence and dose-dependence for Ry action at the RyR. We conclude that the RyR 2 and RyR 3, identified by RT-PCR, play a central role in [Ca2+]i oscillations in gut epithelial cells.

Characterisation of plasmids from diketogluconic acid producing strains of Gluconobacter oxydans

Gluconobacter oxydans ATCC 9937, which produces 2,5-diketogluconic acid, an intermediate in vitamin C synthesis, has three plasmids of sizes 27.7 kb (pVJ1), 12.3 kb (pVJ2) and 18 kb (pVJ4). A restriction map was constructed of pVJ1. A potential glucose dehydrogenase gene was located on pVJ1 using the polymerase chain reaction with heterologous primers. Two other G. oxydans strains had no detectable plasmid DNA (IFO 12258) and a plasmid (pVJ3) of 9.4 kb (IFO 3293), respectively.

Physical characterization of plasmid pMQV10 from a steroid biotransforming strain of Micrococcus

The presence of a single plasmid 8.5 kb in size has been demonstrated in a cholesterol biotransforming strain of Micrococcus. A detailed physical map of the plasmid has been constructed using various restriction enzymes. Streptomycin resistance has been localized on a 1.8-kb fragment of pMQV10.

Intergeneric protoplast fusion between Gluconobacter oxydans and Corynebacterium species

Intergeneric protoplast fusion between 2,5-diketo-gluconic acid producing Gluconobacter oxydans (ATCC 9937) and a mutant strain of Corynebacterium species (ATCC 31090), capable of reducing 2,5-diketo-gluconic acid to 2-keto-L-gulonic acid, a penultimate step in vitamin C production) resulted in viable recombinants. Some of the fusion products exhibited the capacity to convert D-glucose to 2-keto-L-gulonic acid, but the conversion rate is low.

Introduction of a Micrococcus plasmid in Escherichia coli

A 6-MDa plasmid (pMQV10), carrying cholesterol hydroxylase and streptomycin-resistance genes, from a gram-positive strain of Micrococcus sps., (RJ6) has been successfully transformed in gram-negative Escherichia coli K12 C600. pMQV10 is maintained stably and expresses its drug resistance in the new host.

The World Fertility Survey: an appraisal of methodology

"In the first half of the article, a broad account of content and procedures is given. In conduct of individual surveys, the achievements of the World Fertility Survey were based on thoroughness rather than technical superiority. The later aspects of the program, including analysis, archiving, and data dissemination, were more innovative and represent models of excellence for similar future enquiries. In overall terms, the program is judged to be an expensive success. In the second half of the article, two methodological issues are discussed in more detail: the collection of retrospective birth histories and the translation of survey instruments into local languages." Comments by Anthony G. Turner (pp. 768-9), Kweku T. de Graft-Johnson (pp. 769-70), Burton Singer (pp. 771-2), and Joel E. Cohen (pp. 772-4) are appended.

A fast spheroplast formation procedure in some 2,5-diketo-D-gluconate- and 2-keto-L-gulonate- producing bacteria

Calcium 2-keto-L-gulonate (Ca-2-KLG, a key intermediate in vitamin C synthesis) is produced from calcium 2,5-diketo D-gluconate (Ca-2,5-DKG) by a variety of bacteria. A few bacterial species which efficiently convert glucose to Ca-2,5-DKG have been isolated in our laboratory. Our bacterial collection included species that possess the genes for production of Ca-2-KLG from Ca-2,5-DKG; however, the yield of the former is poor. A procedure for the preparation of spheroplasts in Ca-2,5-DKG- and Ca-2-KLG-producing bacteria was developed for the construction of recombinants (fusants), combining the genes for conversion of glucose to Ca-2-KLG efficiently by protoplast fusion. The standard procedure for spheroplast formation in Gram negative bacteria by the Tris-sucrose-EDTA-lysozyme system did not work in the organisms under investigation. The need for an alternative method was necessary. Our results show that, while the Tris-NaCl-EDTA-lysozyme system (pH 8.3) worked very well with bacterial strains of Gluconobacter oxydans (ATCC9937) and Acetobacter melanogenus (NCIM2259), the Tris-sucrose-EDTA-lysozyme system worked well for Erwinia herbicola (ATCC21998), Pseudomonas chlororaphis (NCIM2041) and Corynebacterium species (ATCC31090). However, none of these systems produced spheroplasts in Brevibacterium ketosoreductum (ATCC21914), for which a separate system is under development.

An economical large-scale procedure to purify Micrococcus plasmid DNA

A reproducible and economical procedure for obtaining a large yield of highly purified covalently closed circular (ccc) plasmid DNA from an industrially important strain of Micrococcus is described. The procedure adopted here departs in several ways from commonly used protocols for isolation of plasmid DNA from Gram (positive) and Gram (negative) bacteria. The plasmid DNA prepared by this procedure is free of contaminants and is pure enough to be used for electron microscopy, DNA transformation, sequencing, in vitro transcription and mutagenesis.

Structural alterations in the membrane of the slow muscle fiber of Rana temporaria after denervation

Mixed fiber bundles as well as separated slow and fast fibers from normal and denervated muscles of Rana temporaria were freeze-fractured. The membranes of both fiber types are distinguished in this species by the presence of fairly regularly distributed particle aggregates or arrays of different shapes and sizes; the number per unit area of the membrane is six times higher in fast than in slow fibers. The intramembrane particle (IMP) density is higher in slow than in fast fibers. After denervation, the fast fiber membrane structure does not change whereas the slow fiber membrane acquires the characteristics of the fast fiber, i.e., an increase in the density of particle arrays and a decrease in IMP density. These changes in the slow fiber membrane are compared to the altered physiological properties of this fiber type after denervation.

Complete censuses and samples

"Complete decennial censuses are needed for small areas and other domains. Sample surveys yield diverse and timely data. Censuses can also be combined with samples, and sometimes with data from registers, for diverse estimates that are detailed over both space and time, and hence are timely for small domains. Methods of 'postcensal estimates' for small domains are described. We note uses of censuses for improving samples and of samples for improving censuses, and propose a method for cumulating data from 'rolling' (or rotating) periodic (weekly, monthly or quarterly) samples specifically designed to cover the population in detail over designed spans (annual and quinquennial)."

An evaluation of total parenteral nutrition using Vamin and Aminosyn as protein base in critically ill preterm infants

A total of 75 preterm infants with gestation less than 32 wk received total parenteral nutrition (TPN) using Vamin and Aminosyn as protein base lasting more than 20 days. They were monitored for signs of liver dysfunction, cholestatic jaundice, and TPN-induced metabolic bone disease (osteopenia of prematurity). It was observed that severity of TPN-induced cholestasis depends on the duration of TPN and quantity of protein infused. When used as a protein base, Vamin seemed to be superior to Aminosyn. TPN-induced metabolic bone disease was strongly correlated to the duration of TPN. We suggest close monitoring of critically ill preterm infants on TPN for quantity of protein infusate, liver dysfunction, cholestatic jaundice, and TPN-induced metabolic bone disease. Intravenous protein intake should be limited to less than 2.5 g/kg/day in preterm infants with gestation less than 32 wk.

A comparative study of the membrane structure in different types of muscle fibers in the frog

The muscle membrane of slow and fast fibers in cruralis and iliofibularis muscles and of intermediate fibers in submaxillaris muscle of the frog is studied in freeze-fracture replicas. A comparison of membrane folds, number, size and distribution of caveolae and of intramembrane particles (IMP) is given. In slow muscle fibers, the membrane folds are systematically present at the level of the I zone with a transversal continuity, whereas in fast and intermediate types the membrane folds are small and are randomly distributed. In slow muscle the caveolae are more numerous at the I zone than in the part corresponding to the center of the sarcomere. In fast muscle, small groups of caveolae form linear patterns, and in intermediate fibers the distribution is random. The number of caveolae in slow muscle fibers is two times more than in fast and intermediate fibers. The mean area of caveolae opening is largest in fast and smallest in slow muscle fibers. The number of IMP is significantly different in the three types of fibers, being highest in slow and lowest in intermediate fibers. The different pattern of folds in slow fibers may correspond to the different contractile properties of this fiber type. The presence of double the number of caveolae in slow fibers correlated to the less elaborate T system in this fiber type shows the possibility that slow fibers may be the result of an arrest during development for the performance of a different function. The difference in IMP density in the three muscle fiber types may be interpreted as the difference in their electrical properties.

Structure and distribution of neuromuscular junctions on slow muscle fibers in the frog

Neuromuscular junctions on slow fibers in frog cruralis muscle have been examined with light and electron microscopy. The slow fiber bundle of this muscle is approximately half slow fibers and half fast twitch fibers. Each slow fiber has two-five clusters of nerve terminals in its central region. In contrast, fast fibers in the same bundle have single anastomosing neuromuscular junctions. The average length of terminal clusters on slow fibers is half that of the terminals on fast fibers. Less cholinesterase activity is associated with nerve terminals on slow muscle fibers. The two types of muscle fiber were identified in freeze-fracture replicas by characteristic patterns of the sarcolemmal caveolae and square arrays. Presynaptic membranes of terminals on fast fibers have long, paired double rows of intramembrane particles which lie along the sides of ridges aligned above each fold in the muscle. Ridges are less prominent or absent in terminals on slow fibers and the associated membrane particles are more often in single rows. The lengths of the particle rows also tend to be shorter and rows tend to branch and to lie at various orientations with respect to the longitudinal axis of the terminal. The average length of the particle rows per unit length of nerve terminal on slow fiber terminals is half that of particle rows on fast fiber terminals. It is concluded that the total length as well as the concentration of these active zone specializations is less at terminals on slow fibers. The lack of parallel orientation of the presynaptic active zones at slow fiber terminals corresponds to a lack of postsynaptic folds. Postsynaptic specializations seen in thin sections through slow fibers are either on flat expanses of sarcolemma or on low sarcolemmal bulges. Patches of large intramembrane particles, similar to those on fast fibers, mark regions of postsynaptic specialization in freeze-fracture replicas of slow fibers.

The presynaptic active zones in three different types of fibres in frog muscle

Presynaptic active zones were studied in slow, fast and intermediate types of frog muscle fibres in freeze-fracture replicas. In fast fibres, the double rows of paired particles are present on active zone ridges perperdicular to the longitudinal axis of the nerve whereas in slow fibres active zone ridges are rudimentary or absent and double rows of particles occur in all directions, mostly paired, sometimes single. In the intermediate type of muscle fibres both types of active zone deployment coexist on a single muscle fibre.

Innervation and membrane specialization at neuromuscular junctions in submaxillaris muscle of the frog

The submaxillaris muscle of the frog after zinc iodide-osmium staining reveals the presence of polyneural innervation. Cholinesterase staining shows that the longer terminals have postsynaptic folds whereas the smaller terminals (up to 5 micron) lack them. Thin-section electron microscopy shows that muscle fibers with or without an M line have terminals with and without postsynaptic folds. The terminals with postsynaptic folds have presynaptic membrane outpocketings above folds. These outpocketings are rudimentary or absent in the terminals without postsynaptic folds. In longer junctions, the P face of the presynaptic membrane has double rows of paired particles on active zone ridges perpendicular to the axis of the muscle. In smaller junctions active zone ridges are rudimentary or absent and double rows of particles form various patterns. Postsynaptic active zones in longer junctions consist of clusters of particles leaving gaps in between, whereas in the smaller junctions they lack gaps. The polyneural innervation and different deployment of membrane particles at neuromuscluar junctions could be a factor responsible for different physiological properties of this muscle.

Ultrastructural changes in human endometrium at different phases of the menstrual cycle and their functional significance

A review of the ultrastructure of normal human endometrium at different phases of the cycle is presented. The structural changes are correlated to the functional implications in the light of the recent knowledge on the functioning of cell organelles. Relatively undifferentiated cells of the beginning of the menstrual phase become functionally matured, proliferate and later degenerate. The appearance of the nucleolar channel system during the secretory phase coincides with the rise of progesterone level and facilitates the nucleocytoplasmic exchange. The secretion of the endometrial glands consists of glycogen, glycoproteins, lipids and mucopolysaccharides. Large autophagic vacuoles (giant lysosomes) digest various cell components at the end of the cycle. All the lamina functionalis of the endometrium is not shed, a part of it is regressed by focal death (autophagic vacuoles) and by total death (apoptosis) of individual cells.