alpha-Amanitin resistance is developmentally regulated in carrot

Carrot cells are capable of inactivating alpha-amanitin only in embryogenic conditions (regenerating cells and embryoids). Instead, the mutant line a3 is capable of inactivating the drug also in nonembryogenic conditions (vegetative growth). The mutation is dominant in somatic hybrids and is pleiotropic, allowing expression during vegetative growth of other embryonal functions. The inactivation of alpha-amanitin is due to the oxidative activity of tyrosinase.

Sentinel lymph node biopsy in the treatment of breast cancer. Experience in 527 cases

AIM

Knowledge of axillary lymph node status is a key aid to staging and prognosis and it represents a guideline for adjuvant therapy in breast cancer. Despite the morbidity it causes, complete axillary dissection was long the mainstay of treatment. Sentinel lymph node biopsy has proved so reliable in the evaluation of node involvement that axillary node dissection is now generally performed when sentinel node biopsy tests negative.

METHODS

In this 3-phase study, 50 patients were enrolled to evaluate the learning curve of sentinel node biopsy (phase 1, September 1997-January 1998); 256 patients (age range 27-81 years) with infiltrative breast cancer (T <3 cm, clinical N0) underwent level 1 lymph node dissection when the sentinel node tested negative at histopathology (phase 2, February 1998-March 2001); 221 patients with T <3 cm underwent dissection of the sentinel node when it tested negative for metastasis (phase 3, April 2001-March 2005).

RESULTS

The sentinel node was preoperatively detected in 98.6% of cases after peritumoral and intradermic injection of the radionuclide tracer and intraoperatively in 99% (90% with radio-guided surgery, 10% with vital staining). The sentinel node was positive in 15% of patients with T1 and metastatic in 65%.

CONCLUSIONS

Our results are in line with the published data; therefore, the study will go forward to examine the role of the micrometastasis in the sentinel node and of in-transit tumoral cells.

Risk Factors Associated With Cytomegalovirus Infection in Orthotopic Liver Transplant Patients

Our objective was to investigate the potential risk factors associated with cytomegalovirus (CMV) infection.

PATIENTS AND METHODS

From January 1999 to December 2001, 163 liver transplantations were performed in 154 patients. The study inclusion criteria were absence of retransplantation and survival of more than 6 months. One hundred fifteen patients met the inclusion criteria. We determined variables such as age, gender, and number of hemecomponents as well as serum IgG CMV status of donors and recipients. We recorded the immunosuppression used by each patient. CMV infection was detected by positive antigenemia.

RESULTS

Recipient mean age was 50 years. The etiology of cirrhosis was viral (n = 57; 49.6%), alcoholic (n = 20; 17.4%), virus and alcohol (n = 15; 13.0%), cryptogenic (n = 14; 12.2%), or other causes (n = 9; 7.8%). CMV infection was positive in 75 patients (65.8%). There was no relation between infection and age, gender, or CMV IgG donor recipient status, or the number of hemecomponent units. The risk was 3.8-fold higher for patients receiving a three-drug compared with a two-drug regimen. When cyclosporine was used instead of tacrolimus, the risk of CMV infection was 4.3-fold higher. Logistic regression analysis revealed cyclosporine (OD=5.8) and a three-drug regimen (OD=6.7) to have stronger associations with CMV infection.

CONCLUSION

The use of cyclosporine (OD=5.8) and a three-drug regimen (OD=6.7) are risk factors for CMV infection.

Impact of Cytomegalovirus Infection on Long-Term Survival After Orthotopic Liver Transplantation

Cytomegalovirus (CMV) is one of the most common and serious opportunistic infections in solid organ transplant patients. In different series the incidence of CMV infection ranges from 25% to 85%. An indirect effect of infection includes reduced long-term patient and allograft survival. Our objective was to determine the relationship between CMV infection and patient survival after orthotopic liver transplantation.

PATIENTS AND METHODS

From January 1999 to December 2001, 163 orthotopic liver transplantations were performed in 154 patients. The inclusion criteria for this analysis were the absence of retransplantation and survival of more than 6 months. One hundred fifteen patients met the inclusion criteria. CMV infection was detected by positive antigenemia.

RESULTS

CMV infection occurred in 65.8% of patients after orthotopic liver transplantation. Their 5-year survival was 85%, with no difference observed between patients with or without infection (P = .8).

CONCLUSION

CMV infection did not interfere with patient survival after orthotopic liver transplantation.

[Ductal carcinoma in situ of the breast]

The Authors report their experience about 127 ductal carcinoma in situ (DCIS) of the breast. Guidelines for surgical treatment are: radiological or clinical diagnosis, tumor's extension, histological classification, grading and margin status. At the present the Authors prefer breast conserving surgery with tumor margin's study. They report their experience in the last seven years about sentinel node biopsy. Radiotherapy and endocrine therapy are indicated for selected patients; local recurrence after DCIS therapy is 8,1% on a 6,1 years follow-up.

[Breast-conserving surgery in breast cancer]

Breast-conserving surgery is the treatment of choice for the breast cancer T < 3 cm. The local recurrence is a problem of diagnosis and consequent treatment. We enrolled, from 1987 to 2004, 1504 breast cancer. In 803 (53.4%) tumor with T < 3 cm we performed conserving surgery. The sentinel lymph node (SN) technique induce to limit the axillary dissection in patients T1a-b to the SN only if non metastatic and located to the first level, the dissection of the 1st level of the axilla in patients T1c-T2 < 3 cm and SN negative, complete axillary dissection in patients with metastatic SN or located to the 2nd level. Our percentage of local recurrence in the follow-up was 3.5% at 5 years and 6% at 10 years.

Case report: laparoscopic cholecystectomy in situs viscerum inversus

Situs viscerum inversus is a rare condition, in which the organs are transposed from their normal location in the opposite side of the body. The inversion of L-R asymmetry may be complete (SVI totalis) or partial (SVI partialis), whereby transposition is confined to either the abdominal or thoracic viscera. The authors report a case of videolaparocholecystectomy for cholelithiasis successfully performed on a 41-year-old Caucasian woman with situs viscerum inversus totalis. The patient was discharged on the 2nd postoperative day. The symptomatology disappeared right after the intervention, and still now, after a follow-up of six months, is absent. The procedure was safely performed on the patient with no particular difficulties, except for the reverse position of the angle between the operating and exposing trocars, which led to a difficult approach to the Calot triangle when using the right hand of the surgeon.

[Surgical treatment in day surgery of uncertain breast lesions]

AIM

New models of care are proposed to reduce the costs of traditional hospitalization and to improve the utilization of resources in surgery. Day surgery is widely employed in breast surgery. In this study we report the conversion rate and causes in ordinary hospitalization and we identify some contraindications related to breast surgery in day surgery.

METHODS

A cohort study was performed on 306 patients operated on between July 1999 and December 2001 for breast lesions with uncertain interpretation at the clinical and/or instrumental examination. Those patients who lived at a distance of less than 50 km from the hospital, had a telephone, a suitable house, direct family support and, if necessary, could benefit from home health care in addition to hospitalization, were considered as eligible to day surgery. The kind of anesthesia and hospital admission were established after clinical, psycho-emotional, and socio-familiar evaluation of the patients by the surgeon and the anesthetist.

RESULTS

A total of 250 excisional biopsies and 56 biopsies with a Mammotome were performed. Surgery was performed under local anesthesia in 278 patients and general anesthesia in 28 subjects. Observation exceeding 24 hours was only necessary in 10 patients reporting hypotension syndrome and anxiety. The conversion rate in ordinary hospitalization was 0.3%. Postoperative morbidity was 1%.

CONCLUSION

Day surgery is an effective model of care in breast surgery for diagnostic and therapeutic purposes without axillary dissection. A good selection of patients, perfect interdisciplinary collaboration, and an efficient structural organization are necessary to control the complication and conversion rates of traditional hospitalization.

Risk factors associated with cytomegalovirus-positive antigenemia in orthotopic liver transplant patients

The aim of the study was to investigate risk factors associated with cytomegalovirus (CMV)-positive antigenemia in orthotopic liver transplant (OLT) patients. Sixty-nine patients undergoing OLT during 2001 were retrospectively evaluated for CMV antigenemia during a follow-up of 6 months after transplantation for demographic variables, pretransplant donor and recipient CMV serologic status, etiology of liver disease, number of blood transfusions, and type of immunosuppression. Among the 69 patients who underwent 71 OLT in this period, 43 met study criteria. Mean age was 49.7 +/- 10.8 years and 60.5% were men. End-stage liver disease was the indication for liver transplant, except in one case. The most prevalent etiology of liver disease was hepatitis C and/or alcohol in 66% of the cases. CMV-positive status was recorded in 74% of donors and 95% of recipients. None of the CMV-negative recipients received a positive donor allograft. CMV-positive antigenemia was 84% with 12% having two episodes of infection. There was no correlation between CMV infection and age, gender, etiology of liver disease, or number of blood transfusions. However, all patients using cyclosporine had CMV-positive antigenemia compared with 61% using tacrolimus (P <.032). In this study, the incidence of CMV infection after OLT in adult patients was slightly higher than reported in literature. No risk factor was associated with CMV antigenemia; however, this study suggests a higher probability of CMV infection among patients treated with cyclosporine.

[Central venous catheterization: complications of different placements]

STUDY AIM

The aim of this prospective multicentric non-randomised trial was to report the complications of the central venous catheter insertion with different techniques and to assess the advantages of the low lateral approach to the internal jugular vein, according to the technique originally described by Jernigan et al, with our own modifications.

PATIENTS AND METHOD

From January 1993 to August 1997, 2,290 CVC (2,286 by percutaneous puncture and 4 by surgical approach) were placed. The following complications were analysed prospectively: pneumothorax, accidental arterial puncture, more than two punctures of the same vein, necessity to shift to another venous approach, complete failure, malposition of catheter.

RESULTS

The veins the most frequently used were internal jugular vein (48.7%), femoral vein (27%) and subclavian vein (24.2%). Internal jugular vein was punctured especially by low lateral approach (75%) and subclavian vein by infraclavicular approach (92%). With these two placements, the rate of pneumothorax was 0% and 3.1% respectively (p < 0.001), the rate of accidental arterial puncture was 1% and 2.7% respectively (p < 0.03) and the rate of more than two consecutive punctures was 3.1% and 6.3% respectively (p < 0.008).

CONCLUSION

On our experience, we advocate the low lateral approach to the internal jugular vein as first choice technique for venipuncture in both adults and children for both short and long-term central venous approach, because it is associated to high rate of outcome and to low rate of complications in comparison with other techniques.

Sentinel node biopsy for breast cancer: a critical analysis

The concept of sentinel node biopsy, initially introduced for melanoma, has also been used for breast cancer since the 90's, in that, with the increasingly, widespread use of mammographic screening and of other minimally invasive diagnostic procedures, smaller and smaller cancers are now being diagnosed. For these cancers axillary dissection often constitutes overtreatment. For cancers at an initial stage with a low risk of axillary metastases investigation of sentinel lymph nodes enables us the surgeon to assess the axillary lymph-node status and avoid axillary dissection which is responsible for a certain amount of morbidity. Sentinel nodes can be sought using colorimetric or radioisotope methods. To date there is no common consensus of opinion as to which is the better procedure and the respective indications. Both methods allow detection of sentinel nodes in roughly 90% of cases and the combination of the two yields 100% detection rates. It is widely accepted that sentinel node biopsy should be reserved for unifocal tumours which have not been treated previously and which measure less than 15 mm in diameter. The advantages of the procedure are substantial provided it is performed correctly by surgeons properly trained in its use. The learning curve is relatively brief and is based on no more than 30-40 cases.

A novel K+ channel expressed in carrot roots with a low susceptibility toward metal ions

Kdc1 is a novel K+-channel gene cloned from carrot roots, and which is also present in cultured carrot cells. We investigated the characteristics of the ionic current elicited in Xenopus oocytes coinjected with KDC1 (K+-Daucus carota 1) and KAT1 (from Arabidopsis thaliana) RNA. Expressed heteromeric channels displayed inward-rectifying potassium currents whose kinetics, voltage characteristics, and inhibition by metal ions depended on KDC1:KAT1 ratios. At low KDC1:KAT1 ratios, Zn2+ inhibition of heteromeric K+ current was less pronounced compared to homomeric KAT1 channels, while at higher KDC1:KAT1 ratios, the addition of Zn2+ even produced an increase in current. Under the same conditions, the Ni2+ inhibition of the current was also reduced, but no current increase was observed. These effects might be explained by the unusual amino acid composition of the KDC1 protein in terms of histidine residues that are absent in the pore region, but abundant (four per subunit) in the proximity of the pore entrance. Channels like KDC1 could be at least partially responsible for the higher resistance of carrot cells in the presence of metals.

KDC1, a novel carrot root hair K+ channel. Cloning, characterization, and expression in mammalian cells

Potassium is an essential nutrient which plays an important role in many aspects of plant growth and development. Plants have developed a number of highly specific mechanisms to take up potassium from the soil; these include the expression of K(+) transporters and potassium channels in root cells. Despite the fact that root epidermal and hair cells are in direct contact with the soil, the role of these tissues in K(+) uptake is not well understood. Here we report the molecular cloning and functional characterization of a novel potassium channel KDC1 which forms part of a new subfamily of plant K(in) channels. Kdc1 was isolated from carrot root RNA and in situ hybridization experiments show Kdc1 to be highly expressed in root hair cells. Expressing the KDC1 protein in Chinese hamster ovary cells identified it as a voltage and pH-dependent inwardly rectifying potassium channel. An electrophysiological analysis of carrot root hair protoplasts confirmed the biophysical properties of the Kdc1 gene product (KDC1) in the heterologous expression system. KDC1 thus represents a major K(+) uptake channel in carrot root hair cells.

Temperature-dependent functional expression of a plant K(+) channel in mammalian cells

The Arabidopsis thaliana potassium channel KAT1 was expressed and characterized in Chinese hamster ovary cells. KAT1-GFP fusion protein was successfully targeted to the plasma membrane and electrophysiological analysis revealed functional expression of KAT1 only in cells cultured at 30 degrees C. The main biophysical characteristics of KAT1 are similar to those described for the channel expressed in other systems. CHO cells represent an advantageous expression system and may be the system of choice to study the expression, assembly, function, and regulation of plant potassium channels in general.

Peritoneal leiomyoid mesothelioma mimiking a metastasis of papillary carcinoma

The authors describe a rare case of peritoneal mesothelioma. Cytological, histological and immunohistochemical characterization of the tumor allowed the differential diagnosis from papillary carcinoma and suggested the diagnosis of leiomyoid mesothelioma.

Identification and characterization of an 18-kilodalton, VAMP-like protein in suspension-cultured carrot cells

Polyclonal antibodies raised against rat vesicle associated membrane protein-2 (VAMP-2) recognized, in carrot (Daucus carota) microsomes, two major polypeptides of 18 and 30 kD, respectively. A biochemical separation of intracellular membranes by a sucrose density gradient co-localized the two polypeptides as resident in light, dense microsomes, corresponding to the endoplasmic reticulum-enriched fractions. Purification of coated vesicles allowed us to distinguish the subcellular location of the 18-kD polypeptide from that of 30 kD. The 18-kD polypeptide is present in the non-clathrin-coated vesicle peak. Like other VAMPs, the carrot 18-kD polypeptide is proteolyzed by tetanus toxin after separation of coatomers. Amino acid sequence analysis of peptides obtained by digestion of the 18-kD carrot polypeptide with the endoproteinase Asp-N confirms it to be a member of the VAMP family, as is suggested by its molecular weight, vesicular localization, and toxin-induced cleavage.

[The integrated radiosurgical treatment of rectal cancer]

The value of radio-surgical protocols in the treatment of advanced rectal cancer has been studied retrospectively. 21 patients operated between 1986 and 1990 fulfilling some criteria were considered for this study. They were 9 men and 12 women with rectal cancer Duke's stage B2-C; 16 were treated with preoperative radiotherapy (30-35 Gy), 5 were treated with postoperative radiotherapy (40-60 Gy). The operative procedures were 12 anterior resections and 9 Miles operations. The 5 years results were: a) cancer free survival 52%; 2 patients alive with relapse; 2 patients with non cancer related death (DIC, radiation enteritis); d) cancer related deaths 28%; e) local recurrence was observed (3 pts) only in association with metastatic disease; f) no isolated local recurrence was observed. Preoperative radiotherapy with 30-35 Gy is judged the preferred protocol for decreasing the rate of isolated local recurrence and for increasing the survival rate. Omental flap transposition plays an important role in the radio-surgical treatment of advanced rectal cancer.

Evidence suggesting protein tyrosine phosphorylation in plants depends on the developmental conditions

Protein tyrosine phosphorylation plays a central role in a variety of signal transduction pathways regulating animal cell growth and differentiation, but its relevance and role in plants are controversial and still largely unknown. We report here that a large number of proteins from all plant subcellular fractions are recognized by recombinant, highly specific, anti-phosphotyrosine antibodies. Protein tyrosine phosphorylation patterns vary among different adult plant tissues or somatic embryo stages and somatic embryogenesis is blocked in vivo by a cell-permeable tyrosyl-phosphorylation inhibitor, demonstrating the involvement of protein tyrosine phosphorylation in control of specific steps in plant development.

Characterization of chitinases able to rescue somatic embryos of the temperature-sensitive carrot variant ts 11

To characterize the acidic endochitinase EP3, able to rescue somatic embryos of the carrot cell line ts11, the enzyme was purified from the medium of wild-type suspension cultures. Peptide sequences, deduced amino acid sequences of corresponding PCR-generated cDNA clones, serological relation and biochemical properties showed that there were at least five closely related chitinases, four of which could be identified as class IV EP3 chitinases with an apparent size of 30 kDa. Two other proteins were identified as a serologically related class I acidic chitinase (DcChitI) of 34 kDa, and a serologically unrelated 29 kDa class II acidic chitinase (DcChitII), respectively. Additional cDNA sequences, Western and Southern analysis showed the presence of a least two, but possibly more, highly homologous class IV EP3 genes in the carrot genome. Two class IV EP3 chitinases were tested and found to be able to increase the number of ts11 globular embryos formed under non-permissive conditions. One of the class IV EP3 chitinases as well as the class I chitinase DcChitI promoted the transition from globular to heart-stage ts11 embryos. The class II endochitinase and a heterologous class IV chitinase from sugar-beet were not active on ts11. This suggests that there are differences in the specificity of chitinases in terms of their effect on plant somatic embryos.

On the occurrence of somatic meiosis in embryogenic carrot cell cultures

During the establishment of an embryogenic cell line from a carrot hypocotyl explant, processes closely resembling meiotic divisions are seen. A microdensitometric analysis revealed that the amount of cellular DNA diminished in the majority of cells to the haploid level. However, the diploid level was re-established in a matter of a few days. The genetic consequences of this segregation were studied by analyzing restriction fragment length polymorphisms (RFLP) and randomly amplified polymorphic DNAs (RAPD). The results showed that the great majority of embryos regenerated from segregants and that different segregants had different genetic constitutions.

Modulation of auxin-binding proteins in cell suspensions : II. Isolation and initial characterization of carrot cell variants impaired in somatic embryogenesis

Cultured cell lines from carrot (Daucus carota L.) with little or no embryogenic potential were examined for the auxin-binding capacity of their membranes. The lines belonged to different classes: (a) wild-type lines kept in culture for different periods (the longer the period, the lower being their embryogenic potential); (b) variants, isolated after mutagenesis, showing normal growth but a lack of embryogenic response; (c) auxin-resistant lines, isolated as colonies on solid media containing 45 μM 2,4-D; (d) a previously described tumorous line (E9) isolated because of its resistance to hypomethylating drugs. All of these lines showed alterations in auxin-induced, auxin-binding capacity (modulation), i.e. in the non-embryogenic lines the addition of auxin increased the auxinbinding capacity to a very small degree, or removal of the hormone did not produce the proper decrease in that capacity, or both defects could be simultaneously present. Both types of defects were shown to be correctable: after treatments designed to increase the amplitude of modulation, embryogenic capacity was restored in a number of lines.

A carrot somatic embryo mutant is rescued by chitinase

At the nonpermissive temperature, somatic embryogenesis of the temperature-sensitive (ts) carrot cell mutant ts11 does not proceed beyond the globular stage. This developmental arrest can be lifted by the addition of proteins secreted by wild-type cells to the culture medium. From this mixture of secreted proteins, a 32-kD glycoprotein, designated extracellular protein 3 (EP3), that allows completion of somatic embryo development in ts11 at the nonpermissive temperature was purified. On the basis of peptide sequences and biochemical characterization, EP3 was identified as a glycosylated acidic endochitinase. The addition of the 32-kD endochitinase to ts11 embryo cultures at the nonpermissive temperature appeared to promote the formation of a correctly formed embryo protoderm. These results imply that a glycosylated acidic endochitinase has an important function in early plant somatic embryo development.

[Preoperative radiotherapy in locally advanced rectal cancer: risks and complications?]

Adjuvant radiotherapy in advanced rectal cancer is currently considered of interest: preoperative radiotherapy in particular seems to provide better results. However, doubts in its use arise from fear of technical difficulties at surgery and increase of complications. In Authors' opinion, though, preoperative radiotherapy associated with perineal omentoplasty represents a real progress in the management of rectal cancer. Preliminary experience supports this feeling.

A carrot somatic embryo mutant is rescued by chitinase

At the nonpermissive temperature, somatic embryogenesis of the temperature-sensitive (ts) carrot cell mutant ts11 does not proceed beyond the globular stage. This developmental arrest can be lifted by the addition of proteins secreted by wild-type cells to the culture medium. From this mixture of secreted proteins, a 32-kD glycoprotein, designated extracellular protein 3 (EP3), that allows completion of somatic embryo development in ts11 at the nonpermissive temperature was purified. On the basis of peptide sequences and biochemical characterization, EP3 was identified as a glycosylated acidic endochitinase. The addition of the 32-kD endochitinase to ts11 embryo cultures at the nonpermissive temperature appeared to promote the formation of a correctly formed embryo protoderm. These results imply that a glycosylated acidic endochitinase has an important function in early plant somatic embryo development.

A carrot cell variant temperature sensitive for somatic embryogenesis reveals a defect in the glycosylation of extracellular proteins

The temperature-sensitive carrot cell variant ts11c, arrested in somatic embryogenesis after the globular stage, was characterized. The sensitivity to a shift from 24 degrees C (permissive temperature) to 32 degrees C (non-permissive temperature) is greatest at the globular stage of embryogenesis, while cells proliferating in unorganized fashion and plantlets are not affected. Embryogenesis in ts11c is also arrested at the permissive temperature by replacement of conditioned culture medium with fresh medium. The timing of sensitivity of ts11c to medium replacement coincides with the sensitivity to temperature shift. Both sensitivities are recessive in somatic hybrids between ts11c and wild-type cells. Extracellular glycoproteins synthesized by ts11c at the non-permissive temperature contain much less fucose than those synthesized by the wild type. The glycoproteins synthesized by the variant under non-permissive conditions do not accumulate at the periphery of the embryo, as their wild-type counterparts do, but instead show a diffuse distribution throughout the embryo. The defect in ts11c can be fully complemented by the addition of extracellular wild-type proteins. A revertant of ts11c was isolated that simultaneously reacquired temperature insensitivity and normal glycosylation ability. Collectively, these observations indicate that ts11c is not able to perform proper glycosylation at the non-permissive temperature and suggest that the activity of certain extracellular proteins, essential for the transition of globular to heart stage somatic embryos, depends on the correct modification of their oligosaccharide side-chains.

Reversible variations in the methylation pattern of carrot DNA during somatic embryogenesis

Twenty five clones from a carrot genomic library were used as probes to detect variations in the 5-methyl-cytosine pattern during somatic embryogenesis. The majority of them evidenced an invariant pattern. With two clones however, differences were found between the adulttype DNA pattern and the embryonic one. The level of transcription of the relevant DNA fragments during embryogenesis was investigated by Northern blotting. One of the two probes did not show signals in any of the developmental stages whereas the other showed developmentally regulated expression. This fact suggests a novel strategy for cloning developmentally expressed functions.

Isolation and in vitro translation of mRNA from inflorescences of Parietaria judaica

The aqueous extract of inflorescences of Parietaria judaica contains an allergen homologous to the major pollen allergen Par o I (14 kD), as shown by radio-allergosorbent test (RAST) inhibition and immunoblot analysis. Poly(A)+ RNA was obtained from inflorescences and was shown to be able to code in vitro for a protein homologous to Par o I with respect to sodium dodecylsulphate polyacrylamide gel electrophoretic mobility and to antigenic specificity as defined by the binding, in affinity chromatography, to solid-phase IgG of rabbit anti-Par o I antisera, and in RAST inhibition, to IgE antibodies of human reaginic serum pool.

Isolation and developmental characterization of temperature-sensitive carrot cell variants

Carrot cell lines multiply indefinitely in the presence of the auxin 2,4-D. If auxin is removed, the cells regenerate plantlets in a process that closely resembles embryogenesis in vivo. We isolated a temperature-sensitive variant, ts 2, which is unable to regenerate at 31 °C (non-permissive temperature), but does form embryos and plants at 24 °C (permissive temperature). The temperature treatment had no effect on fully differentiated ts 2 plantlets. In other variants (ts 5 and ts 11) cell proliferation was inhibited at the restrictive temperature. These lines were leaky with respect to the inhibition of embryogenesis at 31 °C.

Analysis of the heat-shock protein pattern during somatic embryogenesis of carrot

The pattern of proteins synthesized by carrot cells after heat-shock was analyzed by SDS-polyacrylamide gel electrophoresis. A study was made of the time of appearance and disappearance of the heat-shock bands and a comparison was made of the heat-shock proteins present in cell extracts obtained from cell suspensions, callus, protoplasts and the different stages of somatic embryogenesis.From this comparison a number of differences and hence of stage-specific markers could be seen. This type of analysis was also carried out in the presence of α-amanitin in order to get information on the type of control of heat-shock protein synthesis. It turned out that in all stages after the initial globular stage, α-amanitin does not alter the heat-shock protein pattern suggesting pre-existence of the relative mRNA's.

Genetic effects of griseofulvin on plant cell cultures

Griseofulvin induces metaphase arrest and polyploidization in plant cells in culture; after which a process of chromosome segregation follows. During this process spontaneous or induced recessive mutations become expressed through the formation of homozygotes or monosomics. This finding can be of use whenever the isolation of recessive mutations is needed and haploid culture is difficult.

[Regulation of the renin-angiotensin-aldosterone system. Role of the prostaglandins]

PRA (in the supine and erect subject) and urinary sodium before and after acute treatment (100 mg i.m.) and chronic treatment (100 mg per os for 8 days) were examined in two groups of subjects with no signs of cardiovascular or renal disease. It was found that indomethacin, which is a well-known inhibitor of prostaglandin synthesis, reduced PRA levels in basal conditions and as a result of postural stimulation, without causing any appreciable change in urinary sodium. Regulation of the PRA on the part of the renal prostaglandins is postulated and its probable mechanisms discussed.

[Acute sepsis caused by "Gaffkya tetragena" in adult with hypogammaglobulinemia (author's transl)]

A case of acute sepsis caused by Gaffkya tetragena in an adult with acquired hypogammaglobulinemia has been described. The Authors pointout the importance that particular conditions of disreactivity and/or of immunodeficiency can play in the acquistion of pathogenicity by Gaffkya tetragena. In the case under discussion a high deficit of IgG and IgA was demonstrable, which had previously caused a long series of infective bacterial diseases.