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Biomedical subjects

P Mali

Publications and source records attributed to P Mali.

At least 19 recordsLinked to original sources
PubMed2006

Microleakage of restorative materials: an in vitro study.

The present study was conducted with the aim of evaluating and comparing the microleakage of glass ionomer, composite resin and compomers. Class V cavities were made in thirty intact caries free premolars and restored with restorative materials to be tested respectively. The teeth were thermocycled and subjected to silver nitrate dye penetration. They were subsequently sectioned buccolingually. Microleakage was evaluated under a stereomicroscope and data subjected to statistical analysis. The study concluded that microleakage was evident in all restorative materials, with glass ionomer showing maximum leakage followed by composite resin. Compomer demonstrated the best results with minimum leakage.

Bicuspid↗
PubMed2005

Immunoreactive antigens of the outer membrane protein of Aeromonas hydrophila, isolated from goldfish, Carassius auratus (Linn.).

Aeromonas hydrophila causes disease under stress conditions or in concert with infection by other pathogens in goldfish. Sero-diagnostic and/or immunoprophylactic tools against Aeromonas infection in goldfish are not available so far. The present study was undertaken to fractionate and characterise the outer membrane proteins (OMP) of A. hydrophila and to identify suitable immunoreactive components. A total of 10 fractions were generated from crude OMP antigens upon gel permeation and subsequent ion-exchange chromatography. One of the fractionated antigens (GPID2), primarily a 57-kDa polypeptide, showed maximum sero-reactivity, even higher than the crude OMP. Suitability of GPID2 antigen for use in diagnostic preparations was assessed by dip-stick ELISA. In vitro goldfish lymphoproliferative ability of fractionated antigen, GPIID2 (primarily a 23-kDa polypeptide) was observed to be higher than all the fractionated antigens as well as crude OMP. It can be concluded that the 57 kDa and 23 kDa polypeptides of the OMP of A. hydrophila, possessing high immunoreactivity, should be given due attention while preparing immunodiagnostic and immunoprophylatic tools against Aeromonas infections in goldfish.

Aeromonas hydrophila↗
PubMed2004

Oral vinorelbine given as monotherapy to advanced, elderly NSCLC patients: a multicentre phase II trial.

Vinorelbine intravenously (i.v.) demonstrated its efficacy and tolerability in advanced non-small cell lung cancer (NSCLC) patients, including elderly subjects. Since vinorelbine is now available as an oral formulation this phase II open study was designed to evaluate its activity and tolerability in advanced, elderly NSCLC patients. A total of 56 chemonaive patients were recruited from April 2001 through to March 2002. The dosage schedule, already tested in younger NSCLC patients, was 60 mg/m(2)once a week for three weeks (first cycle), followed by 80 mg/m(2) once a week until disease progression or development of unacceptable toxicity. A limited sampling scheme was used for performing pharmacokinetic analysis on 52 of 56 patients enrolled in the study. Treatment was well tolerated with grade 3/4 neutropenia in 11/17 patients (20/30%) and febrile neutropenia in 1 (2%). Six partial responses (11%) and 25 stable disease responses were recorded, with a disease control rate of 55%. Median overall survival was 8.2 months (95% Confidence Interval (CI) [6.2-11.3]). The clinical benefit response rate was 31% on 32 evaluable patients. Pharmacokinetic profiles appeared quite similar to the historical profiles recorded following i.v. administration. Oral vinorelbine appears to be a reasonable alternative to i.v. vinorelbine, both in terms of activity and tolerability, in advanced, elderly NSCLC patients.

Administration, Oral↗
PubMed2002

Epirubicin/docetaxel regimen in progressive breast cancer-a phase II study.

The purpose of this investigation was to evaluate the efficacy and toxicity of 6 months' treatment with the combination of epirubicin and docetaxel in metastatic breast cancer. Thirty-eight women (mean age 51 years, range 35-72) with metastatic breast cancer were treated with a regimen of epirubicin 75 mg/m and docetaxel 75 mg/m every 3 weeks, given 4 times if progression was seen upon evaluation after 4 courses or 8 times in responding/stable patients. The patients received 285 cycles of combination treatment and two treatments with docetaxel or epirubicin alone. When neutropenia with fever was observed, further cycles were given with dose reduction. The median cumulative docetaxel dose was 462 mg/m (range 199-600) and that of epirubicin 476 mg/m (range 199-740). The overall response rate was 54% (95% CI 37-71), with a median duration of response of 14.8 months (95% CI 8.8-27.8). Median time to progression was 12 months, median survival 26 months. Neutropenia below 0.5 x 10 /l occurred following 113 (39%) of the total of 285 cycles given; 21 patients (55%) were hospitalized for febrile neutropenia. We conclude that dose tailoring is required in treatment with an epirubicin and docetaxel regimen to avoid grade 3/4 adverse effects in a significant number of patients treated for metastatic breast cancer.

Adult↗
PubMed2000

Docetaxel and irinotecan (CPT-11) in the treatment of malignant pleural mesothelioma--a feasibility study.

We chose to treat malignant pleural mesothelioma with a combination of docetaxel and irinotecan (CPT-11), because there have been preliminary reports that CPT-11 is active against mesothelioma, and docetaxel and CPT-11 were the most active agents in our in vitro experiments in human mesothelioma cell lines. Fifteen previously untreated patients with pleural mesothelioma (IMIG Stage III-IV) were given docetaxel 60 mg/m2 followed by CPT-11 190 mg/m2 on day 1, repeated every 3 weeks. All the patients were evaluable for toxicity and 13 patients were evaluated for response. No objective responses (complete or partial) were achieved, but there were two minor responses (overall response rate 15%) each of a duration of 4 months. Three patients had stable disease (23%); median time to progression was 7 months. Median survival in all the patients was 8.5 months from the first chemotherapy cycle and 11 months from diagnosis. Toxicity was severe with seven of 15 patients suffering neutropenic fever and six of 15 patients grade 3-4 diarrhea. The trial was discontinued because of toxicity and lack of activity. We do not recommend the combination of docetaxel and CPT-11 using the schedule presented here for further investigation in malignant mesothelioma. However, CPT-11 and docetaxel, individually, still warrant further study in this disease, especially in combination with cisplatin.

Aged↗
PubMed1996

Sequential expression of nucleoproteins during rat spermiogenesis.

Transition proteins and protamines are highly basic sperm-specific nuclear proteins that serve to compact the DNA during late spermiogenesis. To understand their sequential role in this function, transition protein 1 (TP1), transition protein 2 (TP2), and protamine 1 (P1) were assayed by polyacrylamide gel electrophoresis in pools of microdissected, staged seminiferous tubule segments in the rat. The results were compared with immunocytochemical analyses of squash preparations from accurately identified stages of the epithelial cycle. TP2 was the first to appear as a faint band at stages IX-XI, followed by high levels at stages XII-XIV of the cycle. TP1 showed a low expression at stage XII of the cycle and peaked at stages XIII-I, whereas protamine 1 first appeared at stage I of the cycle and remained high throughout the rest of spermiogenesis. Immunocytochemical analyses and Western blots largely confirmed these results: TP2 in steps 9-14, TP1 in steps 12-15, and P1 from late step 11 to step 19 of spermiogenesis. We propose that TP2 is the first nucleoprotein that replaces histones from the spermatid nucleus, and its appearance is associated with the onset of nuclear elongation. TP1 shows up along with the compaction of the chromatin. The two transition proteins seem to have distinct roles during transformation of the nuclei and compaction of spermatid DNA.

Animals↗
PubMed1995

Follicle-stimulating hormone regulates the expression of cyclic protein-2/cathepsin L messenger ribonucleic acid in rat Sertoli cells in a stage-specific manner.

Cyclic protein-2/cathepsin L (CP-2) is secreted by Sertoli cells in a highly stage-specific manner, maximally during stages VI-VII of the rat seminiferous epithelial cycle. We investigated FSH regulation of CP-2 mRNA expression of its cellular localization in isolated staged seminiferous tubular segments. FSH induced a significant increase of CP-2 mRNA expression and its cellular localization in isolated staged seminiferous tubular segments. FSH induced a significant increase of CP-2 mRNA levels in stages IX-I, whereas in stages II-VIII, the levels of CP-2 mRNA were reduced. A similar effect was produced by two cAMP analogs, dbcAMP (0.2 mM) and Sp cAMP (20 microM). FSH and cAMP did not affect on the levels of SGP-2 mRNA during the seminiferous epithelial cycle. The magnitude of the response was time- and dose-dependent; the maximum was obtained with 100 ng/ml of FSH. It is likely that FSH regulates Cp-2 gene transcription, since de novo RNA synthesis was required for the stimulatory FSH effect on CP-2 mRNA levels, while ongoing protein synthesis was not. In conclusion, the data suggest that FSH, via cAMP-mediated pathway, regulates CP-2/cathepsin L gene transcription in rat Sertoli cells and modulated the stage-specific expression pattern.

Animals↗
PubMed1995

Haploid gene expression: temporal onset and storage patterns of 13 novel transcripts during rat and mouse spermiogenesis.

The temporal and spatial expression of thirteen novel spermatid-specific genes corresponding to cDNA clones isolated from an adult mouse testis library was analyzed. Northern analysis of RNA from seminiferous tubules at defined stages of the rat and mouse seminiferous epithelial cycle and in situ hybridization of testis sections revealed that these mRNAs were expressed in a stage-specific manner. The expression of all mRNAs was first detected in early round spermatids, and it increased to abundance during stages VII-VIII of the epithelial cycle. Twelve out of thirteen mRNAs were found not only in round spermatids but also in transcriptionally inactive elongated spermatids, suggesting that they are stored and regulated at the translational level. The variation in the length of the poly(A) tail was detected for four of the transcripts, represented by cDNA clones MTEST70, MTEST627, MTEST641, and MTEST643 at defined stages of the cycle. Similarity in the stage-specific expression pattern displayed by this group of haploid-specific genes strongly suggests the presence of common regulatory mechanisms that act during spermiogenesis, and these genes also provide a means for further studies of these mechanisms.

Animals↗
PubMed1994

Localization of urokinase- and tissue-type plasminogen activator mRNAs in rat testes.

The expressions of urokinase (uPA) and tissue-type plasminogen activators (tPA) in different stages of the rat seminiferous epithelial cycle were analyzed by in situ and Northern hybridizations combined with zymographic analysis. Irradiated rat testes were used to assess the cell localization. Both of the plasminogen activators were expressed in a strictly stage specific manner. Maximal expression of uPA mRNA was seen in Sertoli cells during stages VII-VIII of the cycle. The same expression in the basal compartment of the tubules was detected at 7 days post-irradiation (p-i), during a selective reduction of spermatogonia and preleptotene spermatocytes. Levels of tPA mRNA started to accumulate in Sertoli cells at stage VIII and were high during stages IX-XII and detectable during stages XIII-XIV. At 26 days p-i, reduction of pachytene spermatocytes, which are shown to be immunoreactive for tPA, did not have an effect on tPA mRNA expression. Catalytic activities of uPA and tPA changed concomitantly to their RNA levels in different stages of the cycle. However, at 7 days p-i, uPA activity was decreased at stages VII-VIII of the cycle suggesting that germ cell Sertoli cell interaction is important for uPA activity.

Animals↗
PubMed1992

Expression of beta-nerve growth factor and its receptor in rat seminiferous epithelium: specific function at the onset of meiosis.

beta-Nerve growth factor (NGF) is expressed in spermatogenic cells and has testosterone-downregulated low-affinity receptors on Sertoli cells suggesting a paracrine role in the regulation of spermatogenesis. An analysis of the stage-specific expression of NGF and its low affinity receptor during the cycle of the seminiferous epithelium in the rat revealed NGF mRNA and protein at all stages of the cycle. Tyrosine kinase receptor (trk) mRNA encoding an essential component of the high-affinity NGF receptor was also present at all stages. In contrast, expression of low affinity NGF receptor mRNA was only found in stages VIIcd and VIII of the cycle, the sites of onset of meiosis. The low-affinity NGF receptor protein was present in the plasma membrane of the apical Sertoli cell processes as well as in the basal plasma membrane of these cells at stages VIIcd to XI. NGF was shown to stimulate in vitro DNA synthesis of seminiferous tubule segments with preleptotene spermatocytes at the onset of meiosis while other segments remained nonresponsive. We conclude that NGF is a meiotic growth factor that acts through Sertoli cells.

Animals↗
PubMed1991

Stage- and cell-specific gene expression and hormone regulation of the seminiferous epithelium.

The regulation of spermatogenesis seems to involve complex cell interactions in the testis. Little is known about these cellular communication events. Advances in molecular technology and cell or cell group separation methods have made it possible to analyze function of defined spermatogenic and Sertoli cells, thereby giving some insights into the paracrine regulation of spermatogenesis. In this review we will describe how seminiferous tubule segments with distinct cell associations can be rapidly isolated and how the cell composition can be modified by high-energy X-irradiation. Results of the recent studies performed using these techniques will be briefly summarized. Spermatogenic cells at defined stages of their development can be isolated in living condition for morphological and biochemical studies by the transillumination technique. For accurate identification of the stages of the seminiferous epithelial cycle, phase contrast microscopy of live cell squashes has been used. The criteria described by Leblond and Clermont (Am. NY Acad. Sci., 55:548-573, 1952) can be used for accurate recognition of most of the stages of the cycle. However, stages I and II and substages of VII that are important in several studies are difficult to distinguish. Therefore, in addition to the morphology of early spermatids, development of the flagella at step 16 of spermiogenesis and the changing morphology of the cytoplasmic lobes (residual bodies) at stage VII of the cycle were used as criteria for rapid identification and isolation (preparative) of the seminiferous tubule segments. Expression of nucleoprotein and heat shock protein 70-related protein genes was analyzed with Northern blot, slot blot, and in situ hybridization techniques in accurately staged seminiferous tubules. Accurate stage-dependent timing of the onset of transcription, followed by storage and disappearance of the messages was demonstrated. The chromatoid body (cb) has been proposed to have a specific function in storage of the long-lived mRNAs in the spermatids. It is an actively moving cytoplasmic organelle that interacts with Golgi complex during formation of the acrosomic system. The chromatoid body is apparently also dependent on cytoplasmic microtubules, since its movements are inhibited and its structure becomes abnormal in the presence of vincristin, an inhibitor of tubulin polymerization. Follicle-stimulating hormone (FSH) is an important regulator of Sertoli cell function. Since both basal and FSH-dependent cyclic AMP (cAMP) production by seminiferous tubules showed marked stage dependency, Sertoli cells are apparently influenced by spermatogenic cells. Thus, Sertoli cell function varies cyclically depending on the stage of the seminiferous epithelial cycle to provide an optimal microenvironment for spermatogenesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

In vitro stimulation of stage-specific deoxyribonucleic acid synthesis in rat seminiferous tubule segments by interleukin-1 alpha.

Levels of rat testicular interleukin-1-like factor (tIL-1) have been shown to correlate with DNA synthetic activity during the cycle of the rat seminiferous epithelium, suggesting its role as a spermatogonial or meiotic growth factor. To explore this further, a new in vitro model system was developed. Rat seminiferous tubule segments from stages I, V, VIIa, and VIII-IX of the cycle were isolated by transillumination-assisted microdissection, cultured in chemically defined serum-free medium supplemented with human recombinant IL-1 alpha, and labeled with [3H]thymidine. During incubation, spontaneous progression of spermatogenesis was noted. Inactive stage VIIa tubule segments differentiated to stage VIII and initiated DNA synthesis, and concomitantly started to secrete IL-1-like factor. DNA synthesis of stages VIII-IX ceased through differentiation of spermatocytes to leptotene-zygotene (stages XII-XIII of the cycle). IL-1 alpha stimulated DNA synthesis significantly in spermatogonia of stage I. Meiotic DNA synthesis at stage VIIa was stimulated (48 h/34 C) and maintained at stages VIII-IX (48 h/34 C). IL-1 alpha seems to act as a regulator of spermatogenic DNA synthesis in both mitotic and meiotic phases. It has mainly stimulating and maintaining effects, but it may also be inhibitory under certain conditions.

Animals↗
PubMed1990

Stage- and cell-specific expression of the ornithine decarboxylase gene during rat and mouse spermatogenesis.

Ornithine decarboxylase (ODC) is an enzyme that has been shown to be induced in the growth, differentiation and proliferation of cells. We have used a cDNA probe to determine ODC mRNA levels in different stages of the cycle of rat and mouse seminiferous epithelium. For Northern and slot-blot hybridizations, RNA was isolated from microdissected staged seminiferous tubules. Cell-specific localization of ODC mRNA was studied by in situ hybridization. In the rat, in situ hybridization showed increasing mRNA levels during prophase of meiosis with the highest mRNA levels seen in late pachytene spermatocytes and step 3-5 spermatids. In the mouse, the mRNA levels increased in a similar fashion and the highest mRNA levels were found in step 1-8 spermatids. In the rat, Northern blot hybridizations revealed three molecular sizes of ODC mRNA: 2.2, 2.7 and 1.6 kb. The levels of all molecular sizes were highest in stages VII-VIII, and the lowest mRNA levels were seen in stage I of the seminiferous epithelial cycle. The level of the 2.2 kb transcript was low during stages XIII-I. In the mouse, the Northern blot hybridizations also showed three molecular sizes of ODC mRNA: 2.2 and 2.7 kb and very low levels of 1.6 kb transcript. The levels of the transcripts were steady throughout the cycle. In the mouse, the 2.2 kb transcript was more abundant than the 2.7 kb transcript indicating a species difference between rat and mouse in the usage of the two polyadenylation signals within the ODC gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Cellular regulation of basal and FSH-stimulated cyclic AMP production in irradiated rat testes.

Basal and follicle-stimulating hormone (FSH)-stimulated cyclic AMP (cAMP) productions by seminiferous tubular segments from irradiated adult rats were investigated at defined stages of the epithelial cycle when specific spermatogenic cells were low in number. Seven days post-irradiation, depletion of spermatogonia did not influence the basal cAMP production, but FSH response increased in stages II-VIII. Seventeen days post-irradiation when spermatocytes were low in number, there was a small increase in basal cAMP level in stages VII-VIII and FSH-stimulated cAMP production increased in stages VII-XII and XIII-I. At 38 days when pachytene spermatocytes and round spermatids (steps 1-6) were low in number, a decreased basal cAMP production was measured in stages II-VI and IX-XII. FSH-stimulated cAMP output increased in stages VII-XII but decreased in stages II-VI. At 52 days when all spermatids were low in number, basal cAMP levels decreased in all stages of the cycle, whereas FSH response was elevated only in stages VII-XII. All spermatogenic cell types seem to have an effect on cAMP production by the seminiferous tubule in a stage-specific fashion. Germ cells appear to regulate Sertoli cell FSH response in a paracrine way, and a part of cAMP may originate from spermatids stimulated by an unknown FSH-dependent Sertoli cell factor. The FSH-dependent functions may control such phenomena as spermatogonial proliferation, final maturation of spermatids, and onset of meiosis.

Animals↗
PubMed1990

Modulation of basal and FSH-dependent cyclic AMP production in rat seminiferous tubules staged by an improved transillumination technique.

The stage-dependent action of follicle-stimulating hormone (FSH) in the rat seminiferous epithelium was investigated in microdissected 1 mm tubule segments, where the precise stage of the cycle was identified by a rapid screening method of live cell squash preparations. For distinction of stages I and II and the substages of VII, new criteria were used. The step 16 spermatids with rapid assembly of outer dense fibers leading to marked increase of flagellar thickness were used for distinction of stages I and II. The form and density of the cytoplasmic lobes of step 19 spermatids was used for recognition of substages of VII. Highest basal production of cyclic AMP (cAMP, measured by radioimmunoassay) was found in stage II of the cycle and stages XIV-I-VI had higher values than did stages VII-XIII. A decline occurred during stage VII and an increase at stage XIV. When stimulated with FSH, highest cAMP secretion was found in stage IV of the cycle; again, stages XIV-I-VI had higher values than did other stages. A small but significant (P less than .01) stimulation was found at substage VIId. FSH-stimulated and basal cAMP productions of different stages were compared, highest values were found at stages IV and XIII, and lowest, at stages VIIa-c and IX of the cycle. Since the FSH-dependent cAMP production is confined to Sertoli cells, and the number of these cells is constant per unit length of seminiferous tubules, the Sertoli cells are obviously under a stage-specific paracrine control by the surrounding spermatogenic cells. Specific steps in cell differentiation, such as spermatogonial proliferation, final maturation of the spermatids (stages I-VII), onset of meiosis (substage VIId), and completion of meiotic divisions (stage XIV) may be involved in this interaction.

Animals↗
PubMed1989

Stage-specific expression of nucleoprotein mRNAs during rat and mouse spermiogenesis.

The expression of mRNAs for a transition protein (TP1) and two variants of protamines (P1 and P2) during rat and mouse spermiogenesis was investigated using cDNA hybridization techniques. Slot-blot analyses from 1-mm segments of seminiferous tubules and in situ hybridization from testis sections showed that the levels of mRNA for TP1 increased in step-7 round spermatids at substage VIIb of the seminiferous epithelial cycle, earlier than that of P1 and P2 at substage VIIc. The mRNA levels of all transcripts remained high during steps 8-13 in both species. In the rat, the mRNA of TP1 disappeared during step 14 between substages XIVa and XIVb. The P1 mRNA levels decreased during steps 15-16 (stages I-III) and the P2 mRNA during step 15 (stage I). In the mouse, TP1 mRNA disappeared during step 13 (stage I). The P1 mRNA level decreased before P2 in step 14 (stage II), whereas P2 was detected up to step 15 (stage V). Northern-blot analyses with all three cDNA probes revealed two sizes of mRNA and their stage-specific expression. The shorter transcripts appeared later than the longer ones, at the steps of spermiogenesis where translation is known to begin. The results suggest that transcription of TP1, P1, and P2 mRNAs starts at specifically defined times during spermiogenesis and that the temporal translational regulation of these mRNAs is different.

Animals↗
PubMed1989

Developmental and differential expression of the ornithine decarboxylase gene in rodent testis.

Ornithine decarboxylase (ODCase) is the first and rate-limiting enzyme in the polyamine biosynthetic pathway and it is androgen regulated in the mouse. The expression of ODCase transcripts during testicular development was examined by Northern blot analysis with a mouse ODCase cDNA probe. Total RNA was isolated from the testes of prepubertal mice at 6, 8, 12, 16, 18, 20, 22, and 30 days of age, from enriched populations of germinal cells obtained from the testis of immature (8 days old) and mature (45 days old) mice and from several mouse somatic tissues. The level of the two ODCase transcripts (2.2 and 2.7 kilobases) was low but detectable in the testes of 6- to 16-day-old mice and increased substantially as the first spermatogenic wave proceeded into spermiogenesis. The low ODCase mRNA levels observed in prepubertal mouse testes were confirmed with RNA samples obtained from enriched germ cell populations of type A and type B spermatogonia and interstitial cells obtained from Day 8 mouse testes. In agreement with the developmental studies, ODCase mRNA levels increased substantially in enriched populations of pachytene spermatocytes, round spermatids, and residual bodies/cytoplasts isolated from mature testes. Similar results were obtained by in situ hybridization of sections of rat testes. Reduced levels of ODCase transcripts were detected in RNA obtained from cultured mouse Sertoli cells obtained from the testes of 21-day-old mice and in RNA from liver, brain, heart, spleen, seminal vesicle, and aorta. In contrast, ODCase transcript levels from kidneys of male mice were as high as those detected in testis RNA. Substantial levels of ODCase mRNAs were also found in the epididymis. Analysis of polysome gradients prepared from total testis extracts revealed a distribution of ODCase mRNA in both nonpolysomal and polysomal fractions of the gradient, suggesting that ODCase is translationally regulated in the mouse testis.

Animals↗