Poly (triethylenglycol monomethacrylate) and poly(glycerol monomethacrylate) cross-linked gel as potential viscoelastics for intraoperative use

Background: The highly swelling poly(glycerol monomethacrylate) gel (polyGLYMA) and hydrophilic polymer poly(triethylenglycol monomethacrylate (polyTEGMA) were tested as potential viscoelastics for intraopertive use in anterior segment surgery. Methods: PolyGLYMA was implanted into the anterior chamber in 5 rabbits, and 40% polyTEGMA in 16 rabbits. The eyes were enucleated 1 week to 3 months after the operation. The corneal endothelium was examined with specular microscopy, and then the whole eye histopathologically. Results: In all eyes of the polyGLYMA group, the clinical findings were characterized by a marked ciliary injection and severe secondary glaucoma, and the histologic ones by a marked inflammatory infiltration and thickening of Descemet's membrane in the anterior chamber angle. Specular microscopy revealed a decrease in the endothelial cell density and polymorphism of the endothelial cells. In the polyTEGMA group, the anterior segment and the fundus were physiologic all the time, and specular microscopy and histologic findings showed no degenerative and/or inflammatory changes. Conclusions: PolyGLYMA proved unsuitable for intracameral application in rabbits. The new polymer polyTEGMA is characterized by high biologic tolerance after its implantation into the anterior chamber of rabbits. PolyTEGMA 40% might be considered as a potential viscoelastic material in humans.     

Continuous low amplitude direct current stimulation of the crushed peripheral nerve accelerates the early recovery of choline acetyltransferase but not of acetylcholinesterase activity in fast and slow muscles

We investigated if continuous 1 μA direct current stimulation of the injured nerve, with the cathode electrode at the distal end of the nerve crush injury (cathode stimulation), accelerated the recovery of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activity in transiently denervated extensor digitorum longus (EDL) and soleus (SOL) rat muscles. ChAT is a specific marker of cholinergic nerve terminals and may reflect axon ingrowth, and AChE reflects the re-establishment of neuromuscular junctions and recovery of muscle activity. Compared to sham operated animals, the cathode (CA) stimulated rats had a statistically significant larger ChAT activity in the EDL and SOL muscles on days 12 and 14 after nerve crush (P < 0.01, n = 6). The difference in ChAT activity between the groups decreased thereafter. Regarding recovery of muscle AChE, CA stimulation of the crushed sciatic nerve did not detectably accelerate the normalization of activity and pattern of AChE molecular forms in the EDL and SOL muscles. This means that the early rise in ChAT muscle activity in CA stimulated rats was not followed by an accelerated normalization of the neuromuscular transmission in the same group. It is more likely that the higher ChAT activity observed after cathode stimulation indicates a higher ChAT content in regenerating motor nerve endings, rather than a greater number of motor axons entering the muscles. It seems possible that cathode stimulation increased ChAT axonal transport, causing the early increase of ChAT content in the nerve endings. This raises the possibility that the axon transport and subsequent secretion of a trophic factor(s) from the nerve to the reinnervated muscle are enhanced as well, thus shortening the overall time of muscle force recovery in the absence of an appreciable acceleration of recovery of the neuromuscular transmission.     

Incidence of IDDM during 1988–1992 in Zagreb,Croatia

Summary The objective of this study was to determine the incidence of insulin-dependent diabetes mellitus (IDDM) in the population of Zagreb, Croatia, during 1988–1992. A centralized diabetes registry was the primary source of data, while secondary sources were used to assess ascertainment. A total of 282 new cases of IDDM were diagnosed in the study period, the primary and secondary sources identifying annually 93–100% of the cases. The annual incidence rate ranged from 5.6 per 100,000 to 6.6 per 100,000. Early fatality in persons older than 50 years was the major cause of underascertainment. The incidence peaked in the 10–14 years age group (12.4 per 100,000), and remained stable after age 24 years. Males had a significantly higher incidence in the 5–9 and 24–44 years age groups. In the 45–54 years age group, females had a significantly higher incidence. No seasonality was observed. Despite the war conditions in Croatia, the low overall IDDM incidence rates did not change significantly during the study period.Abbreviations IDDM Insulin-dependent diabetes mellitus - DKA diabetic ketoacidosis     

Incidence and mechanisms of aminoglycoside resistance inPseudomonas aeruginosa serotype O11 isolates

Summary Mechanisms of resistance to five aminoglycoside antibiotics: gentamicin (G), tobramycin (T), netilmicin (N), amikacin (A) and isepamicin (I), were assessed in 16 clinical isolates ofPseudomonas aeruginosa serotype O11, originating from five hospitals in Bratislava. All isolates werein vitro highly resistant to all mentioned aminoglycoside antibiotics (MIC>32 mg/l). Thirteen isolates produced three aminoglycoside-modifying enzymes (AGME), responsible for resistance to the respective aminoglycosides: AAC(6)-I (T, N, A); APH (2) (G, T); APH (3)-VI (I). In addition to this, in four isolates a production of AAC(3)-II (G, T, N) was observed. In three isolates no production of AGME was observed. The strains studied were isolated mainly from urine. Several isolates were able to transfer aminoglycoside resistance by bacterial conjugation toP. aeruginosa 1008 rif^r recipient. The transconjugants from these transfers expressed the same resistance pattern and nearly the same mechanisms of resistance as the donor strains.

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Inzidenz und Mechanismus der Aminoglykosid-Resistenz beiPseudomonas aeruginosa O11-Isolaten

Zusammenfassung Bei 16 klinischen Isolaten vonPseudomonas aeruginosa Serotyp O11 aus fünf Krankenhäusern in Bratislava wurde der Mechanismus der Resistenz gegen fünf Aminoglykosid-Antibiotika untersucht; Gentamicin (G), Tobramycin (T), Netilmicin (N), Amikacin (A) und Isepamicin (I). Alle Isolate warenin vitro hochresistent gegen alle genannten Aminoglykosid-Antibiotika (MHK-Werte >32 mg/l). 13 der Isolate bildeten drei Aminoglykosid-modifizierende Enzyme (AGME), die für die Resistenz gegenüber den entsprechenden Aminoglykosiden verantwortlich waren: AAC(6)-I (TNA): APH (2) (G, T): APH (3)-VI (I). Zusätzlich wurde bei drei Isolaten die Produktion von AAC(3)-II (G, T. N) beobachtet. In drei Isolaten fand sich keine Produktion von AGME. Die untersuchten Stämme waren überwiegend aus Urin isoliert worden. Mehrere der Isolate waren fähig, die Aminoglykosid-Resistenz durch bakterielle Konjugation auf denP. aeruginosa 1008 rif^r Rezipienten zu übertragen. Die Transkonjugate von diesen Übertragungen exprimierten dasselbe Resistenzmuster und wiesen nahezu denselben Resistenzmechanismus auf wie die Spenderstämme.

     

Increased muscle stiffness after anterior cruciate ligament reconstruction – memory on injury?

Residual impairment of knee function was tested in 25 patients 6 to 12 months after successful unilateral reconstruction of the anterior cruciate ligament. The control group comprised 25 healthy individuals. Jumping onto one foot from a height of 20 cm was taken as a prototype of similar everyday activities. We measured maximum flexion of the knee during the landing phase of the jump, and the degree of knee flexion at the time of maximum deceleration of the knee against gravity during jumping using the three-dimensional optical motion analysis system-ELITE. In the group of patients, measured parametres were significantly smaller on the operated side than on the unaffected side. These two measured values were significantly smaller on both legs in group of patients as compared to the values in the control group. The results of our study indicate that functional disturbance persisted for 6 to 12 months after anterior cruciate reconstruction. This may be due to the changed muscle activation pattern of the knee causing increased stiffness of knee muscles. It seems that re-programming of the central nervous system occurred in order to protect the injured lower extremities from another injury.     

SORB-GEL method of analysis of 99mTc-labelled compounds

A SORB-GEL method has been worked out for analysing ^99mTc-labelled compounds which (in a few minutes) enables the pertechnetate content to be determined in a preparation. The method is based upon a different tupe of behaviour of ^99mTc-labelled compound, pertechnetate in the columns packed with Sephadex G-10, and with alumina during elution with saline.Polythene syringes 4.7 cm long and 1 cm in diameter were used as chromotographic columns. A syringe packed with Sephadex G-10 transferred 0.1 ml of ^99mTc-labelled compound into the column, and the activity of the column was then measured in the ionisation chamber. Using a syringe, 20 ml of saline was foreced through this column. The eluate was then removed. Using an injection needle, a second column, packed with alumina, was connected with the first. Similarly, a third column, packed with Sephadex G-10, was connected to the second. Through all of them 40 ml of saline was forced. The third column containing Sephadex G-10 was then disconnected and its activity was measured in the ionisation chamber. The pertechnetate content in the preparation was then calculated from the measured values.The method is suitable for determinating the free pertechnetate content in strong and weak chelate compounds and in particle preparations.     

Intracerebral haematoma in an infant with haemophilia A

Summary A nine-weeks-old infant with haemophilia A developed an intracerebral haematoma. Intracranial operation and removal of the haematoma were performed safely under the cover of highly potent AHF cryoprecipitate. Computerized tomography of the brain is very useful for neurosurgical care of the haemophiliac patients as a noninvasive and atraumatic method of examination. The literature of intracranial operations in infants with haemophilia A under the age of one year is reviewed.     

Rickettsiae and rickettsioses in Portugal

The only rickettsiae recorded in Portugal till now were Rickettsia conorii and Coxiella burnetii. Boutonneuse fever is one of the most important transmissible diseases in Portugal. Though the annual number of cases is not exactly known, it is estimated to be not far from 20,000 in some years. Q fever is the other rickettsiosis widely disseminated throughout the country. The serological prevalence and the incidence of those rickettsioses in Portugal are presented in this communication. In recent research in southern Portugal, about 4,000 adult ticks of nine species were screened by the haemocyte test for rickettsiae and rickettsia-like organisms (RLO). In addition to R. conorii three microscopically different RLO were observed. Two of them, i.e. ovoid and bacillary-like, were positive in the immunofluorescence test with spotted fever (R. conorii) antiserum. The first occurred mainly in Rhipicephalus sanguineus ticks, the second one also in other tick species. The latter agent was cultivated in half-engorged R. sanguineus females and in Vero cells. The third organism was found in R. sanguineus, where it exhibited a massive infestation in haemocytes resembling that seen in experimentally infected ticks with C. burnetii, but not being this agent. The investigation of the isolates and their identification and characterization are being continued.Presented at the 4th International Symposium on Rickettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

Molecular Motion of Drugs in Hydrocolloids Measured by Electron Paramagnetic Resonance

The effects of a polymer, the Li-salt copolymer of methyl-methacrylic acid, and its methyl ester on the motion of drug molecules in hydrocolloids were studied. The investigation was carried out by means of electron paramagnetic resonance (EPR) using the model nitroxide tempol, and the spin-labeled drugs lidocaine (si-lid) and dexamethasone (sl-dex). Synthesis of sl-dex was performed. Spin-labeled molecules dissolved in hydrocolloids undergo a fast reorientation motion. The decreasing order of rotational correlation times () —sl-dex > si-lid > tempol—suggests that the size and the shape of the molecules strongly affect their motion. The inhibition of motion of larger molecules depends also on their flexibility. The values indicate proportionality of the microviscosity of hydrocolloids to the polymer concentration. Rotational motion is dependent on the local environment conditioned by the free spaces between polymer molecules.