[Surgical management of the colorectal carcinoma liver metastases]

INTRODUCTION

Unfortunately, the Czech Republic rates of the colorectal carcinoma are the highest in the world. Surgical procedures for colorectal carcinoma liver metastases (JMKRK) are well established and have good long-term outcomes.

AIM

The aim of the study was to assess own results with a reference on modern trends in liver surgery.

SUBJECTS AND METHODOLOGY

From 01- 01- 2000 to 01-12- 2008, a total of 442 liver procedures in 346 patients with colorectal carcinoma liver metastases were performed in the Faculty Hospital and the Charles University Medical Faculty Surgical Clinic in Plzen.

RESULTS

The 30-day postoperative mortality rate was 0.3%, the morbidity rate was 8.1%. Five years following the liver procedure for the colorectal carcinoma liver metastases, 34.0% of the subjects are surviving. 3 years following radiofrequency ablation (RFA) of the colorectal carcinoma liver metastases, 35.5% of the patients are surviving.

CONCLUSION

Nowadays, surgical management of the colorectal carcinoma liver metastases is the method of choice. The other alternative is radiofrequency ablation (RFA) in non-resectable colorectal carcinoma liver metastases. However, currently, only 20% of the patients are operable using the radical methods at the time, when the diagnosis is established. Therefore, the new trends in liver surgery include several-stage/phase, combined procedures and re-resections, aimed to improve resecability of the colorectal carcinoma liver metastases with low patient postoperative mortality and morbility rates.

Cytokines and liver regeneration after partial portal vein ligation in porcine experimental model

THE AIM OF STUDY

The limits of liver surgery are restricted today by the functional reserves of remnant parenchyma. The aim of this article was to acquaint the general surgical and medical public with the results of experimental liver regeneration stimulated by cytokines and thus to enhance their effort to carry on with implementing the research results in clinical practice.

METHODS

Authors present their experimental model of liver regeneration after ligation of portal branches for caudate and right lateral, and right medial liver lobes. The regeneration was induced by application of TNF-alpha and IL-6 into the non-occluded portal branches, and compared with the results of other experimental teams.

RESULTS AND CONCLUSION

The absolute volume of hypertrophic lobes increases after application of TNF-alpha more rapidly, whereas in the control group, practically no changes were recorded in hypertrophic liver lobes volumes in first three days. The achieved acceleration of growth of hypertrophic liver lobes after application of TNF-alpha and IL-6 confirmed the key role of studied pleiotropic cytokines in the priming of liver parenchyma regeneration after portal vein ligation (Fig. 3, Ref. 26).

[Treatment strategy in non-parasitic benign cysts of the liver]

The authors present the problems of treatment of benign non-parasitic cystic liver diseases. Recent diagnostic and treatment strategy is demonstrated at the cohort of 25 patients (16 women and 9 men), who were operated on Department of Surgery, Medical School and Teaching Hospital Pilsen, Charles University Prague between years 2002-2007. The average age was 59.9 years (38-86 years). We performed 15 laparoscopic fenestrations, 5 opened fenestrations, three enucleations of cysts and one left lobectomy and one central liver resection. The resections were performed because of diagnostic uncertainty to verify histological character of leasions at patients after previous operation of gastrointestinal tract for malignancy. Histological diagnosis was proved in 16 cases solitary liver cyst, in 7 cases of polycystic liver disease, one biliary cystadenoma and one retentive cyst. The reoperation of symptomatic solitary liver cyst was performed in one patient after 12 months from primary operation. The average follow-up of patients after surgical treatment was 41 months (5-96 months). Solitary liver cysts are indication to laparoscopic fenestration with biopsy in case of evidence of symptoms. Polycystic liver diseases are treated conservative and surgical treatment is indicated at outstanding and apparent symptomatology of this disease, where is possible to demonstrate preoperatively one or more dominant cysts.

[Carcinoma of the gallbladder--current surgical treatment options]

BACKGROUND

The effect of radical resection in gallbladder cancer is still area of debate.

AIM OF STUDY

To determine the criteria of surgery in primary and incidental gallbladder cancer. method: Eighty-four patients with gallbladder cancer were evaluated between 1999 and 2008. Sixty patients (72.4%) were symptomatic. Explorative laparotomy was performed in 40 (66.7%), palliative procedure in 5 (8.3%) patients in stage pT3-4, N1, M0-1. Cholecystectomy only or completed with wedge resection of the gallbladder bed and lymfadenectomy as radical procedure was performed only in 7 (1.7%) patients in pT1-2, N0-1, M0. Twenty four (28.6%) patients had incidental gall bladder carcinoma. Radical cholecystectomy was performed in 4 (16.7%) - pT1a, N0, M0, palliative cholecystectomy in 3 patients (12.5%) - pT3, N1, M0. Radical reoperation was performed in 15 (62.5%) patients in stage pT1b-2, N0-1, M0.

RESULTS

Patients survival after explorative laparotomy and palliative procedures was no longer than 7 months. Four from seven patients died after radical operation 12-18 months after operation. Six from 15 radically re-operated patients are alive in interval 4 months and 8 years. Nine patients died in interval 9 months and 4 years after re-operation.

CONCLUSION

Radical surgical procedure is the treatment of choice for patients with gall bladder carcinoma especially in stage pT1-2, N0, M0.

[Liver cystadenoma with ovarian stroma--a case review]

Cystadenoma with ovarian type of stroma is a rare liver tumor. Authors discuss diagnostic difficulties and troublesome therapy with potential complications at unfavourable central localization in the liver of 46 years old woman.

Clinical relevance of the expression of mRNA of MMP-7, MMP-9, TIMP-1, TIMP-2 and CEA tissue samples from colorectal liver metastases

BACKGROUND

Nowadays we know that survival rates do not differ between repeated and single liver resections for colorectal liver metastases (CLM). To be able to determine patients prone to early recurrence, the use of different markers with a better prognostic value than the routinely employed tumor markers is required.

AIM OF STUDY

The aim of our study was to assess mRNA expression of MMP-7, MMP-9, TIMP-1, TIMP-2 and CEA in tissue samples from CLM and their relationship to disease-free interval (DFI) and overall survival (OS).

PATIENTS AND METHODS

The liver tumor biopsies were obtained from 40 patients suffering from CLM treated with radical surgery. mRNA expression levels of CEA, MMPs and TIMPs and a housekeeping gene (GAPDH) were quantified using RT-PCR.

RESULTS

The increased expression of CEA, MMP-9 and TIMP-1 in CLM was associated with a short DFI and a high tendency to early CLM recurrence. Statistical analysis confirmed CEA, MMP-9 and TIMP-1 expression as prognostic factors of survival.

CONCLUSION

This study demonstrated the importance of CEA, MMP-9 and TIMP-1 in the prognostication of DFI and OS.

[Tumorous stem cells--a novel view in oncology?]

Authors present contemporary knowledges, arguments and hypothesis about cancer STEM cells and their relations to current concepts of oncology and surgical oncology. The aim is to introduce new view of carcinogenesis and origin of metastatical process as a diseas of STEM cells to general surgical public that deal with surgical oncology and is confronted with new trends in modern oncological pharmacology. The presented theory of tumour origin by cancer STEM cells is confronted critically with all current theories.

Tumor markers as useful predictors of survival rate after exploratory laparotomy for liver malignancies

BACKGROUND

Tumor markers are used for the prediction of relapse and in determining the effect of postoperative or post-oncological therapy as a standard component of follow-up. Metastatic processes of the liver and primary malignancies of the liver and gall bladder are very common in the European population. The aim of this study was to demonstrate the behaviour of malignancy in patients who have not undergone surgical therapy and to study serum levels of the monitored tumor markers in relation to the life expectancy of these patients.

PATIENTS AND METHODS

The Log-rank test and Wilcoxon test were used for statistical evaluation. Survival was computed using the Kaplan-Meier method. Serum levels of the tumor markers conventionally used in clinical practice in patients with gastrointestinal tumors (CEA, CA19-9, C724) and the markers of the proliferation activity in malignancy (TK, TPA, TPS) were studied.

RESULTS

One hundred and nine patients who underwent exploratory laparotomy without any surgical therapy between September 1999 and June 2005 were studied. For patients with a serum level of CEA, CA19-9 and CA72-4 that was higher than the calculated cut-off hazard ratios of early death were respectively 3-, 5- and 9-fold higher than for patients with serum levels of the same tumor markers below the calculated cut-off. Preoperative serum levels of proliferative tumor markers (TK, TPA and TPS) were not statistically significant for the prediction of early death.

CONCLUSION

The results of the pilot study suggest the importance of tumor markers for the prediction of the short-term survival rate. These markers could be used to supplement classic clinical, laboratory and radiodiagnostic parameters. It would be very helpful for the planning of palliative oncological therapy for patients with liver malignancies who cannot be treated by surgical therapy.

Dynamics of serum levels of tumour markers and prognosis of recurrence and survival after liver surgery for colorectal liver metastases

BACKGROUND

The authors present a statistical analysis of the dynamics of tumour markers and compare these with single serum levels in patients before and after liver surgery for colorectal liver metastases (CLM).

PATIENTS AND METHODS

The serum levels of tumor markers conventionally used in clinical practice (CA19-9, CEA, CA72-4) and markers informing of the proliferation activity of malignancy (TKI TPA, TPS) were statistically analysed. The authors studied 144 patients who underwent liver surgery for colorectal liver metastases between September 1999 and June 2005. Serum levels of tumor markers before surgery (maximally two weeks before the operation), after surgery (maximally one month after the operation - usually on the day of dismission), six months (+/- one month) and twelve months after the surgery (+/- one month) were determined. The Log Rank test and the Wilcoxon test were used for statistical evaluation. The survival rate and disease-free intervals (DFI) were computed using the Kaplan-Meier method.

RESULTS

The statistical analysis of tumour marker dynamic after liver surgery (speed and power of recurrence) supported the dynamics of CA 19-9 and CEA as excellent prognostic factors of early recurrence of CLM in contrast to proliferative tumor markers.

CONCLUSION

The results of the study suggest the importance of tumour markers for the prediction of a short survival rate or DFI. This approach would be very helpful for the planning of palliative oncological treatment for patients with liver malignancies that cannot be treated by surgical therapy. Current patients with a high tendency of recurrence of CLM after liver surgery should be followed up more thoroughly to increase the possibility of successful reoperation.

[Pyogenic abscesses of the liver]

Pyogenic abscesses of the liver represent a serious nosologic unit with high morbidity and mortality rates. Their diagnostics is based on ultrasonography, computer tomography or MRI, or positrone emission tomography. The principal treatment procedure includes percutaneous draining of the abscess cavity under the ultrasound or CT control. The authors present a group of 83 subjects hospitalized from 2000 to 2006 for pyogenic abscesses of the liver. Obstruction of the bile ducts, acute cholecystitis and resections of the liver or pancreas for malignancies were recorded as the commonest causes of the abscesses. Percutaneous drainage was the treatment method of choice in 67.5% of the subjects and it included management of the causative factors and administration of antibiotics. The hospitalization period was affected by the following factors: septic conditions (p < 0.04), ALT levels (p < 0.003) - cut off 3.0 mkat/l, the abscess diameter, which may have required reoperation, (p < 0,05), diabetes mellitus (p < 0.05) and septic conditions (p < 0.001). The need for re-hospitalization due to a relaps of the pyogenic abscess of the liver correlated significantly with the following: a number (> 2) of abscesses (p < 0.04), C-reactive protein levels (p < 0.005) - cut off> 100 mg/l and septic conditions (p < 0.007). Furthermore, significat correlation was detected between the mortality rates and sepsis (p < 0.05).

Evaluation of a recombinant human gelatin as a substitute for a hydrolyzed porcine gelatin in a refrigerator-stable Oka/Merck live varicella vaccine

Background

The labile nature of live, attenuated varicella-zoster virus (Oka/Merck) requires robust stabilization during virus bulk preparation and vaccine manufacturing in order to preserve potency through storage and administration. One stabilizing ingredient used in a varicella-zoster virus (VZV) vaccine is hydrolyzed porcine gelatin which represents the major protein/peptide-based excipient in the vaccine formulation.

Methods

In this comparative study, a recombinant human gelatin fragment (8.5 kD) was assessed as a potential replacement for hydrolyzed porcine gelatin in an experimental live, attenuated VZV (Oka/Merck) vaccine. VZV (Oka/Merck) was harvested in two formulations prepared with either a hydrolyzed porcine gelatin or a recombinant human gelatin. Moreover, the viral stability in the experimental VZV (Oka/Merck) vaccines was evaluated under accelerated and real-time conditions in a comparative study.

Results and discussion

The stabilizing effect of recombinant human gelatin on VZV (Oka/Merck) potency change during vaccine lyophilization was similar to the experimental vaccine containing porcine-derived gelatin. Vaccine viral potency changes were comparable in stabilized VZV (Oka/Merck) formulations containing either hydrolyzed porcine gelatin or recombinant human gelatin. No statistically significant difference in potency stability was observed between the vaccine formulations stored at any of the temperatures tested.

Conclusion

The recombinant human gelatin demonstrated similar ability to stabilize the live attenuated VZV (Oka/Merck) in an experimental, refrigerator-stable varicella vaccine when compared to the vaccine preparation formulated with hydrolyzed porcine gelatin used in currently marketed varicella vaccine.

[Portal vein embolization--increased chance for liver resecability for malignancies]

INTRODUCTION

Liver surgery for liver malignancy is recently limited not by technical possibilities but by physiological reserves of liver parenchyma. Portal vein embolization (PVE) is performed to increase future liver remnant volume (FLRV) to extend the possibilities of liver resections. The authors evaluate the cohort of patients, that underwent PVE and confront them with the cohort of patients that underwent liver resection without PVE.

METHODOLOGY

At the Department of Surgery and Departement of Radiology, University Hospital Pilsen there were performed successfully PVE at 24 patients between January 2001 and August 2006. The increase of FLRV was sufficient at 17 patients. The mean period between PVE and computed tomography volumetry was 29 days. The mean period between PVE and surgical procedure was 54 days. 8 patients underwent radical liver surgery (right hepatectomy, extended right hepatectomy, combination of right hepatectomy with RFA in left lobe), 3 patients underwent radiofrequency ablation, the rest of patients was explored. For comparison we used cohort of 107 patients that underwent one step radical surgery for malignancy.

RESULTS

1 year survival rate after liver operation was 85.7%, 3 years survival rate 42.9%. Disease free interval (DFI) was counted only for group of radicaly operated patients. One year DFI was 40%, two year DFI was 20%. The number of leasions was not proved as statistically significant for DFI or survival rate. In non PVE group 1 year survival rate was 78.9%, 3 years survival rate was 34.0%, one year DFI was 60.2%, two years DFI was 36.6%.

DISCUSSION

The survival rate was higher in PVE group, the DFI was shortened in PVE group. In our cohort we could conclude, the PVE increase survival rate instead of shortened DFI. PVE spreads possibilities for liver resections at patients with small FLVR and enables radical surgical therapy for patients, that will be leaved a palliative surgery or oncological therapy.

[Liver hemangiomas--diagnostic and treatment strategy]

Liver hemangiomas are benign mesenchymal tumors or the liver. The majority of them are asymptomatic, diagnosed accidentally during abdominal examination for other reasons. Ultrasonography. computer tomography and magnetic resonance are the main diagnostic instruments. Symptomatic, large cavernous hemangiomas or hemangiomas located on the liver surface with a risk of rupturing because of their size, are indicated for surgical management or radiointervetion. The authors present a patient group of 34 subjects with cavernous hemangiomas of the liver indicated for surgery (N = 25), or radiointervention (N = 9), based on the above critera. The thirty-day mortality rate was nil and morbididty 5.9%. The authors recommend enucleation of the hemangioma, which is technically simple and safe. From a long-term perspective, radiointervention is frequently poorly effective, and, therefore, should be indicated in polymorbid patients.

The rare benign liver tumors

As opposed to malignant secondary tumors, metastases of the colorectal carcinoma are benign tumors of the liver that are quite rare in the Czech Republic. From the 55 patients operated on since 2000 at our department for benign liver tumors, the most frequent are haemangiomas, focal nodular hyperplasia (FNH) and hepatocelular adenoma. Only 7.3% of them form a different histological type of a tumor than this most frequently occurring trio of tumors. The authors describe three cases of rather rare liver tumors with benign behavior that have the potential of becoming malignant. It concerns mucin producing biliary tumors, which correspond to the pancreatic intraductal papillary mucin tumor, hepatic cystadenoma with ovarian stroma and a liver hamartoma in an adult patient (Ref 13). Full Text (Free, PDF) www.bmj.sk.

[Prognostic factors of early recurrence of colorectal liver metastases and their usage in clinical praxis]

Liver surgery for colorectal liver metastases (CLM) is very often followed by recurrence. The prediction of early relapse of CLM is important for successful treatment, long disease free period and for long survival of patients, because it could help us to choose adequate surgical and oncological treatment. The authors present contemporary overview of the prognostic factors of early CLM recurrence and their possible use in prognostic scoring systems. These could be very helpful in clinical practice.

[A partial relaps of a colorectal carcinoma metastatic process following liver surgery--a multifactorical study]

In the period of November 1999 - June 2003 78 patients with colorectal liver metastases (CLM) were operated at Department of Surgery, University Hospital in Pilsen. In multifactorial analysis there were evaluated these clinical parametres: age of patient, sex, localisation of primary tumor, Dukes classification, grading, staging and histology of primary tumor, histologicaly free resection margin, chemotherapy or actinotherapy after colorectal operation, type of liver resection, complications after liver surgery, radicality of liver surgery, lateralisation of liver metastatic process, number of metastases, blood transfusions, repeated liver surgery, volume of metastases. Kaplan-Meier method was used for evaluation of survival rate and disease free interval (DFI). Statistical analysis of studied clinical parametres was performed by Log-rank test and Wilcoxon test. The medium DFI after liver surgery was 16 months for all the patients (range 0-55 months), the medium DFI for patients after radical surgery was 18 months. The medium survival time after liver surgery for all the patients was 30 months (range 1-57 months), for patients after radical surgery it was 32 months, and for patients after palliative surgery the medium disease free interval was 29 months (range 5-30 months). The 4-year survival rate after the liver surgery was for all the patients 37%. The factors statistically significant for a disease free interval after liver surgery were bilaterality of metastatic process, the microscopically free resection line, radical surgical treatment versus RFA and unilaterality of metastatic process. The authors proved followed factors as statistically significant for survival rate: grading of colorectal cancer and age of patients. The prediction of early recurrence enables us to choose adequate surgical therapy or its extension by oncological therapy. More thorough follow up of patients with tendency to early recurrence of CLM helps to early diagnosis of relaps and it increases the posssibility of repeated liver surgery.

Immunosuppresive agents have an influence on ischemia-reperfusion injury in kidneys procured from a non-heart-beating donor: experimental study

Ischemic-reperfusion injury (IRI) has a considerable influence on the function of kidneys from non-heart-beating donors (NHBD) after transplantation. IRI is accompanied by a marked inflammatory reaction with the production of reactive oxygen species and of the proinflammatory cytokine tumor necrosis factor alpha. The effect on the development of ischemic-reperfusion injury of early treatment of the donor with mycophenolate mofetil and tacrolimus was monitored in an animal model of a NHBD. The study demonstrated that the combination of the two immunosuppressives reduced the production in the NHBD kidney of tumor necrosis factor alpha, an indicator of the degree of inflammatory reaction after reperfusion, to a considerable extent but not of malondialdehyde or reduced glutathione. Pre-treatment of marginal donors with these immunosuppressants may improve the immediate function of transplanted kidneys by reducing cytokine production.

Markers of cellular adhesion in diagnosis and therapy control of colorectal carcinoma

AIM

Early diagnosis of the progressive tumor disease and control of the effect of therapy in colorectal carcinoma are most frequently performed by monitoring CEA or CA 19-9 tumor markers. Their clinical application is, however, limited. The aim of our study was to demonstrate the contribution of adhesive molecule assessment to the early diagnosis of progression. We also wanted to find out if changes in the levels of cellular adhesion parameters correlate with the effect of antitumor therapy.

MATERIALS AND METHODS

Intercellular cell adhesive molecule-1 (ICAM-1) and Vascular cell adhesive molecule-1 (VCAM-1) were assessed using the ELISA method, and the results were correlated with CEA and CA 19-9 tumor markers. Three hundred and sixty-four patients with colorectal carcinoma in Dukes' stages B-D were monitored. The results were processed with the SAS 6.2. statistical program and Statistica.

RESULTS

In 92 patients with first clinical progression (occurrence of distant metastases irrespective of localization), significantly increased ICAM-1 and VCAM-1 values were demonstrated. In ROC evaluation of curves, we also demonstrated high sensitivity of adhesive molecules against both the control healthy group (n =89) and the no evidence of disease group (NED) (n=183). Adhesive molecule levels were closely connected with the type and course of therapy and are presented in the form of case reports.

CONCLUSION

Soluble adhesive molecules are a prospective parameter both for the early diagnosis of progression and for control of the effect of therapy. There is a need for a large-scale study, preferably multicentric, which would verify the suitability of introducing cellular adhesion parameter assessment into routine practice.

Surgical treatment of benign liver tumors

In their report, the authors evaluated in their report a group of patients with benign liver tumors. These patients were treated at the Surgical Department of the Teaching Hospital in Pilsen from 1999 up to 2004. The evaluation of the investigated groups compared of 43 sick patients was based on the prospect of their individual diagnoses, types of performed surgeries, the time period of their therapy and complications, which had occurred in the course of their surgical treatment. In the group of 24 patients with liver haemangioma, the authors recorded 14 patients with focal nodular hyperplasia, 3 patients with hepatocellular adenoma and 2 patients with other types of benign tumors--multilocular cystic lymphangioma of the liver and one hamartoma. Among these patients there was 0% mortality and 6.9% morbidity.

Paratuberculosis in farmed and free-living wild ruminants in the Czech Republic (1999-2001)

Due to the occurrence of the infection of Mycobacterium avium subspecies paratuberculosis among domestic ruminants and the rapid development of farmed deer industry and the market of cloven-hoofed game we have carried surveys of paratuberculosis, beginning in 1997, in the most common four species of wild ruminants in the Czech Republic [Pavlik et al., Vet. Microbiol. 77 (2000) 231-251]. From 1999 the prevalence of paratuberculosis has been slightly reduced in all three types of husbandry of wild ruminants. Nevertheless paratuberculosis has been diagnosed in wild ruminants in three districts, in four game parks and in five farms. M. a. paratuberculosis was isolated from 128 (5.3%) out of 2,403 wild ruminants of four animal species: 106 red deer, 2 roe deer, 4 fallow deer and 16 mouflons. In red deer farms, the highest number of clinical paratuberculosis cases was in yearling deer. RFLP type B-C1 of M. a. paratuberculosis predominated during the second period (1999-2001) in all types of husbandry with no relationship to wild ruminant species. New "cattle" RFLP types B-C5 and B-C16 of M. a. paratuberculosis were described in infected farmed red deer and one "intermediate" RFLP type R-I4 in fallow deer from one game park. The survival of M. a. paratuberculosis was found to be 4 months during winter in the pasture after destocking of all cattle infected with paratuberculosis. We found that non-vertebrates, wild ruminants or non-ruminant wildlife can be vectors and potentially become a risk factor in the spread of M. a. paratuberculosis infection.

Convergent evolution of SIV env after independent inoculation of rhesus macaques with infectious proviral DNA

The env gene of three simian immunodeficiency virus (SIV) variants developed convergent mutations during disease progression in six rhesus macaques. The monkeys had been inoculated with supercoiled plasmids encoding infectious proviruses of SIVmac239 (a pathogenic, wild-type strain), SIVdelta3 (the live attenuated vaccine strain derived from SIVmac239), or SIVdelta3+ (a pathogenic progeny virus that had evolved from SIVdelta3). All six monkeys developed immunodeficiency and progressed to fatal disease. Although many divergent mutations arose in env among the different hosts, three regions consistently mutated in all monkeys studied; these similar mutations developed independently even though the animals had received only a single infectious molecular clone rather than standard viral inocula that contain viral quasispecies. Together, these data indicate that the env genes of SIVmac239, SIVdelta3, and SIVdelta3+, in the context of different proviral backbones, evolve similarly in different hosts during disease progression.

Primers ITS1, ITS2 and ITS4 detect the intraspecies variability in the internal transcribed spacers and 5.8S rRNA gene region in clinical isolates of fungi

Restriction fragment length polymorphism analysis of the 5.8S rRNA gene and the internal transcribed spacers (ITS1 and ITS2) was used for examination of 66 isolates belonging to 19 species. Intraspecies variability was found in the examined region of 11 species (Candida albicans, C. catenulata, C. colliculosa, C. glabrata, C. kefyr, C. melinii, C. parapsilosis, C. guillermondii, C. solanii, C. tropicalis, Saccharomyces cerevisiae). Region of ITS-5.8S rDNA was amplified using the primers ITS1 and ITS4. The amplicons were digested by HaeIII, HinfI and CfoI. The recognized intraspecies variability was confirmed in the second step, in which the shorter fragments of this region were amplified using primers ITS1 and ITS2 and analyzed by capillary electrophoresis. Considerable intraspecific variability renders this method unsuitable for species identification, whereas it can be useful for epidemiological tracing of isolates.

Truncated forms of human and simian immunodeficiency virus in infected individuals and rhesus macaques are unique or rare quasispecies

Truncated proviruses of variable sizes are present in peripheral blood mononuclear cells (PBMC) of human immunodeficiency virus type 1 (HIV-1)-infected persons and simian immunodeficiency virus (SIV)-infected rhesus macaques. Here, we investigated whether the highly deleted HIV and SIV proviruses are present in infected organisms as multiple copies or whether each truncated provirus is unique. Using end-point dilution, multiple long-distance (LD) DNA PCR assays were run in parallel using DNA extracted from PBMC of seropositive, treatment-naive persons and from lymph nodes of a rhesus monkey inoculated with cloned, full-length SIVmac239 DNA. The PCR products were titrated and mapped. Most truncated proviruses were present in the DNA samples tested as single, nonintegrated molecules that differed from one another in size and/or nucleotide sequence. These results indicate that truncated primate lentiviral sequences found in infected tissues are unique or rare quasispecies that do not replicate significantly.

[Molecular genetics methods in medical mycology]

Molecular genetic methods that use the polymerase chain reaction (PCR) are due their speed widely employed in diagnostic approaches in microbiology. In this report, the possibilities of application of these methods in medical mycology are discussed with regard not only to species identification, but also for genotyping of strains for epidemiological purposes. Recently, a tendency to exploit molecular genetic methods rather for epidemiological studies than for routine species identification may be observed. With regard to the high inter-species variability, careful standardization using samples of isolates of the tested species from corresponding geographical origin is necessary. Perspectives of future development associated with the explanation of molecular biological relations between human tissues and the pathogen, with the recognition of mechanisms of virulence and resistance to antifungal drugs are discussed.