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Biomedical subjects

R Novak

Publications and source records attributed to R Novak.

At least 19 recordsLinked to original sources
PubMed1991

[Rectal neobladder. A 25-year experience].

On the experience of 153 cases of rectal bladder after cystectomy for cancer, the indications, technique and results of this operations are reported. Earlier, it was a method of choice as a bladder substitute. Today the indication is limited to female cysto-urethrectomy. Technique consists in rectum isolation and ureterorectal antireflux anastomosis; the sigmoid colon is pulled through behind rectum and between outer and inner layer of anal sphincter fixed on the perineum. The overall postoperative mortality is 7.8%, but in the last 5 years there was no mortality. The most frequent complications are sigmoid retraction and its partial necrosis. Micturition mostly is under control, but 14% of patients have a relative defecation incontinence.

Anastomosis, Surgical↗
PubMed1989

Continent sigmoid bladder after cystectomy: 20 years' experience.

Twenty years' experience in the substitution of an isolated sigmoid segment after radical cystectomy for bladder carcinoma is described. The indication for surgery was isolated, non-transitional cell bladder cancer. The isolated sigmoid segment is placed longitudinally in the isoperistaltic direction. The study is made up of 73 cases. This operation does not make the procedure more radical since it does not increase survival for this illness. However, in relation to other bladder substitution methods, it guarantees a better quality of life after the operation.

Aged↗
PubMed1988

Effect of positive-pressure ventilatory frequency on regional pleural pressure.

Regional lung ventilation is modulated by the spatiotemporal distribution of alveolar distending forces. During positive-pressure ventilation, regional transmission of airway pressure (Paw) to the pleural surface may vary with ventilatory frequency (f), thus changing interregional airflow distribution. Pendelluft phenomena may result owing to selective regional hyperventilation or phase differences in alveolar distension. To define the effects of f on regional alveolar distension during positive-pressure ventilation, we compared regional pleural pressure (Ppl) swings from expiration to inspiration (delta Ppl) and end-expiratory Ppl over the f range 0-150 min-1 in anesthetized, paralyzed, close-chested dogs with normal lungs. We inserted six pleural balloon catheters to analyze Ppl distribution along three orthogonal axes of the right hemithorax. Increases in regional Ppl were synchronously coupled with inspiratory increases in Paw regardless of f. However, at a constant tidal volume and percent inspiratory time, end-expiratory Paw and Ppl increased in all regions once a f threshold was reached (P less than 0.01). Supradiaphragmatic delta Ppl were less than in other regions (P less than 0.05), but thoracoabdominal binding abolished this difference by decreasing thoracoabdominal compliance. We conclude that the distribution of forces determining dynamic regional alveolar distension are temporally synchronous but spatially asymmetric during positive-pressure ventilation at f less than or equal to 150/min.

Animals↗
PubMed1988

Effects of local chemotherapy and immunotherapy on the recurrence and progression of superficial bladder cancer.

409 cases of superficial bladder carcinoma (pTa, pTi, Tis) are reported. They are divided into three groups: 171 patients treated by TUR alone, 124 treated by TUR and local thio-TEPA, and 114 patients treated by TUR and BCG vaccine locally. It was found that the frequency of recurrence fell by 56.7, 41.9 and 26.3%, while the progression of the illness declined correspondingly by 19.8, 16.9 and 11.4%. In other words, in terms of recurrence and progression, the poorest results were found for the group treated by TUR only, and the best results were found with the TUR and BCG group.

Administration, Intravesical↗
PubMed1988

Histologic analysis of placental tissue in first trimester abortions.

The value of histologic evaluation in the analysis of material from first trimester abortions is not completely defined. We prospectively analyzed placenta and decidua from 75 first trimester, spontaneous abortions to ascertain if morphologic features were predictive of karyotype. The histologic features analyzed included hydropic villus change, villus fibrosis, villus scalloping with trophoblastic invaginations, atypical stromal cells, aggregates of lymphocytes in placenta or decidua, and acute inflammation of placenta or decidua. Normal karyotypes were observed in 44 cases and abnormal karyotypes were demonstrated in 31. The presence of villus scalloping with trophoblastic invagination was significantly associated with abnormal karyotypes, particularly triploidy, and the demonstration of acute inflammation was seen significantly more often in cases with normal karyotypes. We conclude that histology can provide only a suggestion as to the likelihood of an abnormal karyotype; the findings are not specific enough to obviate the need for karyotyping in the individual case.

Abortion, Spontaneous↗
PubMed1988

Transformation of the female breast during compression at mammography with special reference to the importance for localization of a lesion.

The effects of compression during mammography were studied in 187 breasts. The aims of this study were to investigate: 1) How the skin moves, 2) how the gland tissue is transformed, 3) if there is a relationship between outer and inner alterations and 4) the practical implications for aspiration biopsy. In this study, several experiments were carried out to investigate the effects of compression during clinical mammography in adult female breasts. The transformation of the breast during compression was investigated by means of external skin markings and internal markings using the biopsy needle and the hookwire at preoperative localization. The extent of the mammary gland was measured in the different standard projections during mammography. The calculation of the depth of a lesion during cranio-caudal compression was performed on the latero-medial radiographs. The result was checked with water-soluble radiographic contrast medium. The mean value of differences between observed and calculated depth was 3.7 mm. 1. The breast transforms during compression. 2. The biopsy needle in the breast and the barium markings on the skin incline ventrally in 96 per cent during latero-medial compression. The preoperative hookwire inclines ventrally in 92 per cent. 3. The extension of the gland parenchyma (the longest diagonal) is almost equal in all standard projections, including the medio-lateral oblique one. 4. The skin in the inframammary sulcus is firmly attached to the thoracic wall. This form of fixation determines principally the movements of the breast and limits the transformation during compression. 5. The movements of the skin are connected to the movements of the dense tissue, gland parenchyma. There is a connection between the ventral and descending inclination. These inclinations are caused by the same transformation of the breast. 6. Due to the regular movements of the breast during different compression directions, it is possible to predict the location of a lesion in three dimensions from standard mammograms.

Adult↗
PubMed1987

The respiratory aspect of the treatment of brain injury associated with acute alcohol intoxication--results of an animal experiment.

The effects of spontaneous respiration and mechanical ventilation were examined by investigating the interaction between elevated intracranial pressure and alcohol intoxication. Ethanol (200 ml 48%) was infused in 11 young pigs with elevated cerebral pressure during mechanical ventilation (group 1), 7 young pigs with elevated cerebral pressure during spontaneous respiration (group 2), and 4 young pigs without elevated cerebral pressure during spontaneous respiration (group 3). While the behavior of intracranial pressure during mechanical ventilation in the animals from group 1 was inhomogeneous with a tendency to rise (29-34 mmHg), cerebral pressure (28-55 mmHg) increased drastically in the animals from group 2. This increase was associated with a sharp rise of Pa,CO2 (37.6-73.3 mmHg) and a decrease of Pa,O2 (74 mmHg to 13 mmHg). None of the animals in group 2 survived. Pa,CO2 also rose in alcoholized animals without elevated cerebral pressure (group 3) (41.9-63.9 mmHg); intracranial pressure, however, remained within the normal range. All animals in group 3 survived. Our findings indicate that elevated intracranial pressure and alcohol intoxication have a cumulative or potentiating effect on depression of the respiratory center. Respiratory depression can be prevented by mechanical ventilation and, therefore, a further rise of intracranial pressure generally avoided.

Alcoholic Intoxication↗
PubMed1987

[Course of superficial carcinoma of bladder (Ta-T1). Apropos of 171 cases].

171 patients with superficial bladder carcinoma (Ta-T1) treatment by endoscopic surgery only, were followed during the period from 1.1.1976 to 31.12.1980. The effect of previous tumors in case history, multiplicity, cellular differentiation and tumor size on the frequency of recurrence and tendency to tumor progression was investigated. It was established that the size of tumor most influences the frequency of recurrence, followed by tumors in case history, multiplicity and epithelial anaplasia. A tendency to muscular invasion during recurrence depends mainly on the tumors size and its grade of cellular anaplasia.

Humans↗
PubMed1986

An in vitro comparison of rat and chicken brain neurotoxic esterase.

A systematic comparison was undertaken to characterize neurotoxic esterase (NTE) from rat and chicken brain in terms of inhibitor sensitivities, pH optima, and molecular weights. Paraoxon titration of phenyl valerate (PV)-hydrolyzing carboxylesterases showed that rat esterases were more sensitive than chicken to paraoxon inhibition at concentrations less than or equal to microM and superimposable with chicken esterases at concentrations of 2.5-1000 microM. Mipafox titration of the paraoxon-resistant esterases at a fixed paraoxon concentration of 100 microM (mipafox concentration: 0-1000 microM) resulted in a mipafox I50 of 7.3 microM for chicken brain NTE and 11.6 microM for rat brain NTE. NTE (i.e., paraoxon-resistant, mipafox-sensitive esterase activity) comprised 80% of chicken and 60% of rat brain paraoxon-resistant activity with the specific activity of chicken brain NTE approximately twice that of rat brain NTE. The pH maxima for NTE from both species was similar showing broad, slightly alkaline optima from pH 7.9 to 8.6. [3H]Diisopropyl phosphorofluoridate (DFP)-labeled NTE from the brains of both species had an apparent mol wt of 160,000 measured by sodium dodecyl sulfate polyacrylamide gel electrophoresis. In conclusion, NTE from both species was very similar, with the mipafox I50 for rat NTE within the range of reported values for chicken and human NTE, and the inhibitor parameters of the chicken NTE assay were applicable for the rat NTE assay.

Animals↗
PubMed1985

Directed manual recruitment of collapsed lung in intubated and nonintubated patients.

Four patients with collapsed lung are presented that demonstrate the utility of the directed manual recruitment technique (DMRT) in a range of clinical situations presented by weaning difficulties, recurrent acute atelectasis, and acute respiratory failure in the nonintubated patient. DMRT is an easily applied noninvasive method of lung expansion in the treatment of patients with segmental and lobar collapse and is safe when carried out with appropriate precautions.

Adult↗
PubMed1983

Surgical treatment of urethral stricture: still a problem?

In the introduction the author stresses that the main facts which decide the choice and prognosis of therapy are localization, length and the so-called complexity of the stricture. His 15-year material from 388 operations on 290 patients is presented. Circular strictures of the anterior urethra (a total of 135 operations) are treated through endoscopic urethrotomy as the primary procedure and mostly by open resection as the secondary one. Longitudinal strictures of the anterior urethra (199 operations) are treated by marsupialization, pedicled cutaneous flap and Michalowski's "sleeve" technique as primary procedures. As the secondary procedure (after failure of the first operation) marsupialization only was performed. Complex strictures of the posterior urethra (total 54) were treated mostly by transpubic approach, which showed good results in 74% cases on 41 operations.

Endoscopy↗
PubMed1983

Effect of methylazoxymethanol acetate on rat liver nuclear and nucleolar RNA synthesis.

The effect of methylazoxymethanol acetate on rat liver nuclear and nucleolar RNA synthesis is investigated at various doses (5 to 50 mg/100 g body weight) and for various lengths of time (1 to 24 hr). The results show that this carcinogen is a potent inhibitor of both nuclear and nucleolar RNA synthesis. Like other carcinogens studied previously in this laboratory, e.g., N-hydroxy-2-acetylaminofluorene, aflatoxin B1, and actinomycin D, methylazoxymethanol acetate inhibits RNA synthesis at multiple sites. It impairs chromatin template function and selectively inhibits the activity of RNA polymerase II. Experimental evidence suggests the mechanism of inhibition of RNA polymerase II activity is due to a decrease in catalytic efficiency rather than in the total number of the enzyme. In addition, it is found that methylazoxymethanol acetate induces a dramatic condensation of nucleoplasmic chromatin.

Animals↗
PubMed1983

[Current status of transpubic surgery of the posterior urethra].

The transpubic approach is indicated for repair of complex stenoses of the posterior urethra, fundamental technical points being perineal mobilization of the anterior urethra, dissection of the intercrural septum, symphyseotomy, and direct anterior anastomosis of the two extremities of the urethra. Analysis of results in a personal series of 49 patients operated upon for posterior urethral stenosis showed that good results were obtained in 35 cases (71%), no postoperative endoscopic or surgical procedure being necessary. However, recurrence of the lesion was noted in 6 cases (12%), absolute incontinence following operation in 3 cases (6%), and relative incontinence in 5 cases (10%). Postoperative sexual disorders developed in 11 adults, 8 of these reporting various types of erection difficulties.

Humans↗